ORCID Profile
0000-0002-8467-2845
Current Organisations
Murdoch University
,
University of South Australia
,
South China Agricultural University
,
University of New England
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Publications
Computational Investigation on the Biomechanical Responses of the Osteocytes to the Compressive Stimulus: A Poroelastic Model
Publisher: Hindawi Limited
Date: 2018
DOI: 10.1155/2018/4071356
Abstract: Osteocytes, the major type of bone cells embedded in the bone matrix and surrounded by the lacunar and canalicular system, can serve as biomechanosensors and biomechanotranducers of the bone. Theoretical analytical methods have been employed to investigate the biomechanical responses of osteocytes in vivo the poroelastic properties have not been taken into consideration in the three-dimensional (3D) finite element model. In this study, a 3D poroelastic idealized finite element model was developed and was used to predict biomechanical behaviours (maximal principal strain, pore pressure, and fluid velocity) of the osteocyte-lacunar-canalicular system under 150-, 1000-, 3000-, and 5000-microstrain compressive loads, respectively, representing disuse, physiological, overuse, and pathological overload loading stimuli. The highest local strain, pore pressure, and fluid velocity were found to be highest at the proximal region of cell processes. These data suggest that the strain, pore pressure, and fluid velocity of the osteocyte-lacunar-canalicular system increase with the global loading and that the poroelastic material property affects the biomechanical responses to the compressive stimulus. This new model can be used to predict the mechanobiological behaviours of osteocytes under the four different compressive loadings and may provide an insight into the mechanisms of mechanosensation and mechanotransduction of the bone.
Insulin-like growth factor-I partially attenuates colonic damage in rats with experimental colitis induced by oral dextran sulphate sodium
Publisher: Informa UK Limited
Date: 1998
DOI: 10.1080/00365529850166923
Abstract: Administration of insulin-like growth factor-I (IGF-I) results in selective growth of the gastrointestinal tract. We investigated the effects of IGF-I on the colonic damage induced by oral dextran sulphate sodium (DSS) in the rat. Rats consumed 2% DSS in the drinking water for 10 days to induce colitis. Pumps were implanted on day 3 to deliver IGF-I for 7 days. Colonic histopathology and immunolocalization of transforming growth factor-beta1 (TGF-beta1) were assessed on day 10. Compared with the colon of vehicle-treated rats consuming DSS, IGF-I increased the numbers of goblet cells by 76%, reduced the proportion of lamina propria cells expressing TGF-beta1, and reduced the thickness of submucosal and muscularis externa layers by 26% and 20%, respectively. We conclude that the effects of IGF-I treatment on the colonic epithelium may be mediated directly, whereas the reduced inflammation in the mucosa and submucosa may be mediated by a mechanism other than up-regulation of TGF-beta1-mediated immunosuppression.
Three-dimensional Reconstruction of Peripheral Nerve Internal Fascicular Groups
Publisher: Springer Science and Business Media LLC
Date: 24-11-2015
DOI: 10.1038/SREP17168
Abstract: Peripheral nerves are important pathways for receiving afferent sensory impulses and sending out efferent motor instructions, as carried out by sensory nerve fibers and motor nerve fibers. It has remained a great challenge to functionally reconnect nerve internal fiber bundles (or fascicles) in nerve repair. One possible solution may be to establish a 3D nerve fascicle visualization system. This study described the key technology of 3D peripheral nerve fascicle reconstruction. Firstly, fixed nerve segments were embedded with position lines, cryostat-sectioned continuously, stained and imaged histologically. Position line cross-sections were identified using a trained support vector machine method and the coordinates of their central pixels were obtained. Then, nerve section images were registered using the bilinear method and edges of fascicles were extracted using an improved gradient vector flow snake method. Subsequently, fascicle types were identified automatically using the multi-directional gradient and second-order gradient method. Finally, a 3D virtual model of internal fascicles was obtained after section images were processed. This technique was successfully applied for 3D reconstruction for the median nerve of the hand-wrist and cubital fossa regions and the gastrocnemius nerve. This nerve internal fascicle 3D reconstruction technology would be helpful for aiding peripheral nerve repair and virtual surgery.
Notch2 blockade mitigates methotrexate chemotherapy-induced bone loss and marrow adiposity
Publisher: MDPI AG
Date: 02-05-2022
Abstract: Childhood cancer methotrexate (MTX) chemotherapy often causes bone growth impairments, bone loss, and increased risks of fractures during or after treatment, for which the pathobiology is unclear and there is a lack of specific treatment. Our time course analyses of long bones from rats receiving intensive MTX treatment (mimicking a clinical protocol) found decreased trabecular bone volume, increased osteoclast formation and activity, increased adipogenesis in the expense of osteogenesis from the bone marrow stromal cells at days 6 and 9 following the first of five daily MTX doses. For exploring potential mechanisms, PCR array expression of 91 key factors regulating bone homeostasis was screened with the bone s les, which revealed MTX treatment-induced upregulation of Notch receptor NOTCH2, activation of which is known to be critical in skeletal development and bone homeostasis. Consistently, increased Notch2 activation in bones of MTX-treated rats was confirmed, accompanied by increased expression of Notch2 intracellular domain protein and Notch target genes HEY1, HES1 and HEYL. To confirm the roles of Notch2 signalling, a neutralising anti-Notch2 antibody or a control IgG was administered to rats during MTX treatment. Microcomputed tomography analyses demonstrated that trabecular bone volume was preserved by MTX+anti-Notch2 antibody treatment. Anti-Notch2 antibody treatment ameliorated MTX treatment-induced increases in osteoclast density and NFATc1 and RANKL expression, and attenuated MTX-induced bone marrow adiposity via regulating Wnt/β-catenin signalling and PPARγ expression. Thus, Notch2 signalling plays an important role in mediating MTX treatment-induced bone loss and bone marrow adiposity, and targeting Notch2 could be a potential therapeutic option.
Dioscorea bulbifera polysaccharide and cyclophosphamide combination enhances anti-cervical cancer effect and attenuates immunosuppression and oxidative stress in mice
Publisher: Springer Science and Business Media LLC
Date: 12-01-2016
DOI: 10.1038/SREP19185
Abstract: Cyclophosphamide (CTX) is commonly used in cancer chemotherapy, which causes immunosuppression and tissue oxidative stress at high doses. As potential protective agents, some polysaccharides were shown to have anti-tumor, anti-inflammatory and/or anti-oxidant properties. This study explored potential effects of oral treatment of Dioscorea bulbifera polysaccharides (DBLP at 100 or 150 mg/kg) in U14 cervical tumor-bearing mice treated with CTX (25 mg/kg). While CTX suppressed tumor growth (65.4% inhibition) and DBLP alone also inhibited tumor (25.6% at 100 mg/kg or 37.6% at 150 mg/kg), CTX+DBLP combination produced tumor inhibition rates of 5.6 (for 100 mg/kg DBLP) or 9% (for 150 mg/kg) higher than CTX alone. While tumor itself and CTX treatment reduced thymus and/or spleen/body weight indices, DBLP alone or CTX + DBLP combination attenuated this reduction. DBLP lowered peripheral blood T-cell subpopulation CD 4+ /CD 8+ ratio and DBLP+CTX combination attenuated CTX effect in lifting CD 4+ /CD 8+ ratio. Tumor itself and CTX treatment heightened oxidative stress (with decreased superoxide dismutase but increased lactate dehydrogenase and malondialdehyde levels in serum and tissues), which was attenuated by DBLP treatment and DBLP+CTX combination suppressed CTX-induced oxidative stress. Combination use of DBLP with CTX can potentially enhance CTX anti-tumor effect and can attenuate CTX-induced immunosuppression and oxidative stress in U14 cervical tumor-bearing mice.
Effect of lumbar 5 ventral root transection on pain behaviors: A novel rat model for neuropathic pain without axotomy of primary sensory neurons
Publisher: Elsevier BV
Date: 20-10-190728635
Therapeutic Alliance and Group Cohesion in an Online Support Program for Adolescent and Young Adult Cancer Survivors: Lessons from “Recapture Life”
Publisher: Mary Ann Liebert Inc
Date: 12-2017
Abstract: Psychological support services for adolescent and young adults (AYAs) with cancer are moving online and are increasingly peer based. It is unclear whether online service delivery impacts critical therapeutic elements such as collaborative patient-therapist rapport and group cohesion. AYA cancer survivors (N = 39) participating in a six-week online cognitive-behavioral therapy group program-"Recapture Life"-rated their perception of therapeutic alliance and group cohesion. Participant-rated alliance and group cohesion were high throughout the program, and therapist-rated participant openness, trust, and motivation strengthened over time. The findings provide further support for the expansion of AYA cancer support services to the online domain.
Application of autologous bone marrow derived mesenchymal stem cells to an ovine model of growth plate cartilage injury.
Publisher: Bentham Science Publishers Ltd.
Date: 23-06-2010
DOI: 10.2174/1874325001004010204
Abstract: Injury to growth plate cartilage in children can lead to bone bridge formation and result in bone growth deformities, a significant clinical problem currently lacking biological treatment. Mesenchymal stem/stromal cells (MSC) offer a promising therapeutic option for regeneration of damaged cartilage, due to their self renewing and multi-lineage differentiation attributes. Although some small animal model studies highlight the therapeutic potential of MSC for growth plate repair, translational research in large animal models, which more closely resemble the human condition, are lacking. Our laboratory has recently characterised MSCs derived from ovine bone marrow, and demonstrated these cells form cartilage-like tissue when transplanted within the gelatin sponge, Gelfoam, in vivo . In the current study, autologous bone marrow MSC were seeded into Gelfoam scaffold containing TGF-β1, and transplanted into a surgically created defect of the proximal ovine tibial growth plate. Examination of implants at 5 week post-operatively revealed transplanted autologous MSC failed to form new cartilage structure at the defect site, but contributed to an increase in formation of a dense fibrous tissue. Importantly, the extent of osteogenesis was diminished, and bone bridge formation was not accelerated due to transplantation of MSCs or the gelatin scaffold. The current study represents the first work that has utilised this ovine large animal model to investigate whether autologous bone marrow derived MSC can be used to initiate regeneration at the injured growth plate.
Upregulation of brain-derived neurotrophic factor and neuropeptide Y in the dorsal ascending sensory pathway following sciatic nerve injury in rat
Publisher: Elsevier BV
Date: 1999
DOI: 10.1016/S0304-3940(98)00958-6
Abstract: An immunohistochemical study was undertaken to examine the changes of brain-derived neurotrophic factor (BDNF) and neuropeptide Y (NPY) in the nucleus gracilis of rats following sciatic nerve transection. The results showed that BDNF-immunoreactivity (-ir) in the gracile nucleus was significantly increased after the nerve injury. The upregulation was apparent 24 h after nerve lesion, remaining robust up to 56 days postlesion. The increase in BDNF-ir was blocked by hemisection of the spinal cord, or by dorsal rhizotomy ipsilateral to the lesion. NPY-ir changes were similar to those of BDNF-ir, but the onset was delayed by 7 days. No NPY-ir was detected in dorsal root ganglion (DRG) from normal animals. Following sciatic nerve lesion, most of the NPY-immunoreactive neurones were found to be colocalized with BDNF-immunoreactive neurones. Neutralization of endogenous BDNF with its antiserum had no effects on NPY-ir in either the gracile nucleus or DRG. These results indicate that neurones contributing to the dorsal ascending sensory pathway upregulate the expression of both BDNF and NPY in response to sciatic nerve injury.
Author response: p16 deficiency attenuates intervertebral disc degeneration by adjusting oxidative stress and nucleus pulposus cell cycle
Publisher: eLife Sciences Publications, Ltd
Date: 09-02-2020
Methotrexate treatment suppresses osteoblastic differentiation by inducing Notch2 signaling and blockade of Notch2 rescues osteogenesis by preserving Wnt/ss-catenin signaling
Publisher: Wiley
Date: 03-01-2022
DOI: 10.1002/JOR.25253
Abstract: Methotrexate (MTX) is a commonly used antimetabolite in cancer treatment. Its intensive use is linked with skeletal adverse effects such as reduced bone formation and bone loss, and yet little information is available on molecular mechanisms underlying MTX‐induced impaired bone formation. This study investigated the effects of MTX treatment at a clinical chemotherapy relevant dose on osteogenic differentiation in MC3T3E1 osteoblastic cells. To investigate the potential mechanisms, the expression of 87 genes regulating osteoblast differentiation and bone homeostasis was screened in MTX‐treated versus untreated cells by polymerase chain reaction (PCR) arrays and results illustrated significant upregulation of Notch2 and Notch target genes at both early and late stages of MC3T3E1 differentiation following MTX treatment. To confirm the roles of Notch2 pathway and its potential action mechanisms, MC3T3E1 cells were treated with MTX with an anti‐Notch2 neutralizing antibody or control IgG and effects were examined on osteogenesis and activation of the Wnt/ β ‐catenin pathway. Our results demonstrated that induction of Notch2 activity is associated with MTX adverse effects on osteogenic differentiation and blocking Notch2 rescues osteoblast differentiation by preserving activation of the Wnt/ β ‐catenin pathway.
The Influence of Therapeutic Radiation on the Patterns of Bone Marrow in Ovary-Intact and Ovariectomized Mice
Publisher: Public Library of Science (PLoS)
Date: 06-08-2012
Icariin stimulates the osteogenic differentiation of rat bone marrow stromal cells via activating the PI3K–AKT–eNOS–NO–cGMP–PKG
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.BONE.2014.06.016
Abstract: Icariin, a prenylated flavonol glycoside isolated from Epimedii herba, has been found to be a potent stimulator of osteogenic differentiation and has potential application in preventing bone loss. However, the signaling pathway underlying its osteogenic effect remains unclear. We hypothesized that the osteogenic activity of icariin is related to the nitric oxide (NO) signal pathway and PI3K/AKT pathway in its upstream. Rat bone marrow stromal cells (rBMSCs) were cultured in osteogenic medium and treated with icariin or together with L-NAME, ODQ, PDE5, and/or LY294002 (the inhibitor of NOS, sGC, cGMP, and PI3K respectively), and effects were examined on the expression of signal messengers (NOS, NO, sGC, cGMP, PKG and PI3K) and the levels of osteogenic markers (alkaline phosphatase or ALP, osteocalcin and calcified nodules). It was found that icariin dose-dependently increased ALP activity, and treatment at the optimal concentration (10(-5)M) increased NOS activity, iNOS and eNOS expression, NO production, sGC and cGMP contents and PKG expression besides the phosphorylation of AKT. The addition of L-NAME, ODQ and PDE5 significantly inhibited the icariin effects on above markers respectively. The addition of LY294002 decreased the p-AKT level, NOS activity, eNOS expression and NO production significantly, but had no significant effect on iNOS expression. The addition of any of the four inhibitors also abolished the osteogenic effect of icariin on rBMSCs as indicated by ALP activity, osteocalcin synthesis, calcium deposition and the number and areas of calcified nodules. These results suggest that the osteogenic effect of icariin involves the PI3K-AKT-eNOS-NO-cGMP-PKG signal pathway. Furthermore, dosage response studies showed that icariin at 10(-6)M (a physiologically achievable concentration in vivo) also activated this signal pathway.
Repair of injured articular and growth plate cartilage using mesenchymal stem cells and chondrogenic gene therapy.
Publisher: Bentham Science Publishers Ltd.
Date: 05-2006
DOI: 10.2174/157488806776956904
Abstract: Injuries to the articular cartilage and growth plate are significant clinical problems due to their limited ability to regenerate themselves. Despite progress in orthopedic surgery and some success in development of chondrocyte transplantation treatment and in early tissue-engineering work, cartilage regeneration using a biological approach still remains a great challenge. In the last 15 years, researchers have made significant advances and tremendous progress in exploring the potentials of mesenchymal stem cells (MSCs) in cartilage repair. These include (a) identifying readily available sources of and devising appropriate techniques for isolation and culture expansion of MSCs that have good chondrogenic differentiation capability, (b) discovering appropriate growth factors (such as TGF-beta, IGF-I, BMPs, and FGF-2) that promote MSC chondrogenic differentiation, (c) identifying or engineering biological or artificial matrix scaffolds as carriers for MSCs and growth factors for their transplantation and defect filling. In addition, representing another new perspective for cartilage repair is the successful demonstration of gene therapy with chondrogenic growth factors or inflammatory inhibitors (either in idually or in combination), either directly to the cartilage tissue or mediated through transducing and transplanting cultured chondrocytes, MSCs or other mesenchymal cells. However, despite these rapid pre-clinical advances and some success in engineering cartilage-like tissue and in repairing articular and growth plate cartilage, challenges of their clinical translation remain. To achieve clinical effectiveness, safety, and practicality of using MSCs for cartilage repair, one critical investigation will be to examine the optimal combination of MSC sources, growth factor cocktails, and supporting carrier matrixes. As more insights are acquired into the critical factors regulating MSC migration, proliferation and chondrogenic differentiation both ex vivo and in vivo, it will be possible clinically to orchestrate desirable repair of injured articular and growth plate cartilage, either by transplanting ex vivo expanded MSCs or MSCs with genetic modifications, or by mobilising endogenous MSCs from adjacent source tissues such as synovium, bone marrow, or trabecular bone.
High amplitude and low frequency cyclic mechanical strain promotes degeneration of human nucleus pulposus cells via the NF-kB p65 pathway
Publisher: Wiley
Date: 25-03-2018
DOI: 10.1002/JCP.26551
Abstract: Disc degeneration alters the structure and function of intervertebral discs and is the basis of spinal degenerative diseases. To establish the molecular mechanism of intervertebral disc degeneration caused by mechanical strain, this study examined the effects of different litude (3%, 9%, 19%) cyclic mechanical strain (CMS) at a low frequency (0.01 Hz) on the secretion of cartilage extracellular matrix, expression of inflammatory cytokines and catabolic proteases, and activation of NF‐κB signaling pathway in human nucleus pulposus cells. We also investigated effects of low frequency and high litude (19%) CMS on degeneration of human nucleus pulposus cells in the presence or absence of p65 inhibitor, p65 silencing shRNA, or p65 overexpression. While 3% CMS did not significantly decrease aggrecan or type II collagen expression, or increase TNF‐α, IL‐1β, IL‐6 expression, 9% and 19% CMS showed the significant effects. Low frequency and high litude (19%) CMS was found to promote p65 activation in human nucleus pulposus cells, and IL‐1β was found to promote p65 nuclear translocation though IκB kinase phosphorylation. Furthermore, degeneration process of nucleus pulposus cells was found attenuated in the presence of p65 inhibitor or p65 silencing shRNA, but promoted with p65 overexpression. These data suggest that high litude and low frequency CMS could promote degeneration of human nucleus pulposus cells significantly via the NF‐κB p65 pathway. Our findings have uncovered the effect of CMS on human nucleus pulposus cell degeneration and have identified a previously unknown intrinsic underlying mechanism.
Primary cilium is required for the stimulating effect of icaritin on osteogenic differentiation and mineralization of osteoblasts in vitro
Publisher: Springer Science and Business Media LLC
Date: 21-10-2016
DOI: 10.1007/S40618-016-0568-8
Abstract: Icaritin, one effective metabolite of Herba Epimedii-derived flavonoid icariin, has a strong osteogenic activity. However, its action mechanism remains unclear. Since primary cilia have been shown to play a pivotal role in regulating the osteogenesis, we hypothesized primary cilia are indispensable in mediating icaritin osteogenic effect. Primary rat calvarial osteoblasts were transfected with siRNA1 targeting intraflagellar transport protein 88 (IFT88), a protein required for ciliogenesis, to prevent formation of primary cilium and were treated with 10 Alkaline phosphatase (ALP) activity was significantly increased after 3 days in cells transfected with scrambled siRNA control and treated by icaritin (SC+I group) compared to cells transfected with scrambled siRNA control only (SC group). ALP activity after IFT88 siRNA1 transfection and icaritin treatment (siRNA1+I group) was significantly lower than that of SC+I group. Formation of ALP positively stained colonies after 6 days, osteocalcin secretion after 9 days and formation of calcified nodules after 12 days displayed a similar tendency among the three groups. mRNA expression of osteogenesis-related genes ALP, BMP-2, COL1α, RUNX-2 and OSX after 24 h was significantly increased in SC+I group, but was not different with SC group in siRNA1+I group. Protein levels of BMP-2, COL1α, RUNX-2 and OSX after 48 h showed the similar tendency with gene expression. Primary cilia are important in mediating icaritin-stimulated osteogenic differentiation and may be a novel target for pharmacological therapies for bone loss.
Inflammatory bowel disease: Experimental and clinical: Expression of B7 costimulatory molecules by cells infiltrating the colon in experimental colitis induced by oral dextran sulfate sodium in the mouse
Publisher: Wiley
Date: 11-2001
DOI: 10.1046/J.1440-1746.2001.02558.X
Abstract: T-cell activation, mediated by the interaction with major histocompatibility complex (MHC)-peptide complexes and B7 costimulatory molecules on antigen-presenting cells, is an essential event in the pathogenesis of inflammatory bowel disease (IBD). We investigated the expression of B7 costimulatory molecules on cells in the colon in an experimental mouse model of IBD to determine whether the B7/ligand interaction could provide a target for therapeutic intervention in IBD. Experimental colitis was induced in mice by oral consumption of water substituted with 5% dextran sulfate sodium (DSS). Mice (n=4) were killed 1, 2, 3, 4 and 7 days after commencing DSS consumption, and colonic tissue was collected and examined immunohistochemically for T cells, B cells, macrophages and cells expressing B7-1 or B7-2. Compared to control mice drinking water, macrophage numbers in the colonic epithelium were elevated sevenfold by day 1 and T cells were elevated threefold by day 3 following commencement of DSS consumption. Numbers of infiltrating B7-positive (B7+) cells were not significantly elevated until day 7 when B7-1+, B7-2+ cells and macrophages were increased 20-fold compared to normal mice. These results demonstrate that an initial and rapid infiltration of the colonic epithelium by B7-negative macrophages is followed by an infiltration of T cells and subsequent upregulation of the B7 costimulatory molecules potentiating the inflammatory reaction in this disease model. These results suggest an intervention strategy based on the blockade of the B7-costimulatory axis could find application in the treatment of inflammatory bowel disease.
Adipose-derived stem cells for wound healing
Publisher: Wiley
Date: 04-12-2019
DOI: 10.1002/JCP.27922
Abstract: Wound healing is a complex but a fine‐tuned biological process in which human skin has the ability to regenerate itself following damage. However, in particular conditions such as deep burn or diabetes the process of wound healing is compromised. Despite investigations on the potency of a wide variety of stem cells for wound healing, adipose‐derived stem cells (ASCs) seem to possess the least limitations for clinical applications, and literature showed that ASCs can improve the process of wound healing very likely by promoting angiogenesis and/or vascularisation, modulating immune response, and inducing epithelialization in the wound. In the present review, advantages and disadvantages of various stem cells which can be used for promoting wound healing are discussed. In addition, potential mechanisms of action by which ASCs may accelerate wound healing are summarised. Finally, clinical studies applying ASCs for wound healing and the associated limitations are reviewed.
Bone marrow sinusoidal endothelium: damage and potential regeneration following cancer radiotherapy or chemotherapy
Publisher: Springer Science and Business Media LLC
Date: 27-09-2017
DOI: 10.1007/S10456-017-9577-2
Abstract: It is very well known that bone marrow (BM) microvasculature may possess a crucial role in the maintenance of homeostasis of BM due to mutual interactions between BM microvascular system and other physiological functions including haematopoiesis and osteogenesis. Chemotherapy and radiotherapy are known as main approaches for cancer treatment and also are known as the main cause of damage to the BM microvascular system. However, despite the importance of BM microvasculature in orchestrating various biological functions, less attention has been drawn to address the underlying mechanisms for the damage and to explore cellular and molecular mechanisms by which the recovery/regeneration of chemotherapy- and/or radiotherapy-induced BM microvascular system damage can occur. Therefore, in this review we firstly discuss the ultra-/structure and biological characteristics of BM microvascular system (sinusoids). Secondly, potential contribution of BM sinusoids is discussed in pathophysiological circumstances (bone remodelling, haematopoiesis, cancer bone metastasis, and haematological cancers). Thirdly, we address previous preclinical and clinical studies regarding chemotherapy- and irradiation-induced BM microvasculature damage. Finally, potential cellular and molecular mechanisms are discussed for the recovery/regeneration of damaged BM microvascular system, including the potential roles of endothelial progenitor cells, haematopoietic stem rogenitor cells, and stimulation of VEGF/VEGFR and Ang-1/Tie-2 signalling pathways.
Roles of epidermal growth factor family in the regulation of postnatal somatic growth
Publisher: The Endocrine Society
Date: 23-02-2007
DOI: 10.1210/ER.2006-0049
Abstract: Ligands of the epidermal growth factor receptor (EGF-R), known to be important for supporting tissue development particularly in the gut and brain, have also been implicated in regulating postnatal somatic growth. Although optimal levels of both milk-borne and endogenous EGF-R ligands are important for supporting postnatal somatic growth through regulating gastrointestinal growth and maturation, supraphysiological levels of EGF-R ligands can cause retarded and disproportionate growth and alter body composition because they can increase growth of epithelial tissues but decrease masses of muscle, fat, and bone. Apart from their indirect roles in influencing growth, possibly via regulating levels of IGF-I and IGF binding proteins, EGF-R ligands can regulate bone growth and modeling directly because they can enhance proliferation but suppress maturation of growth plate chondrocytes (for building a calcified cartilage scaffold for bone deposition), stimulate proliferation but inhibit differentiation of osteoblasts (for depositing bone matrix), and promote formation and function of osteoclasts (for resorption of calcified cartilage or bone). In addition, EGF-like ligands, particularly hiregulin, can be strongly regulated by PTH, an important regulatory factor in bone modeling and remodeling. Finally, EGF-R ligands can regulate bone homeostasis by regulating a pool of progenitor cells in the bone marrow through promoting proliferation but suppressing differentiation of bone marrow mesenchymal stem cells.
Intramembranous ossification mechanism for bone bridge formation at the growth plate cartilage injury site
Publisher: Wiley
Date: 03-2004
Tumor necrosis factor superfamily 15 promotes lymphatic metastasis via upregulation of vascular endothelial growth factor‐C in a mouse model of lung cancer
Publisher: Wiley
Date: 20-07-2018
DOI: 10.1111/CAS.13665
Perinatal maternal dietary supplementation of ω3-fatty acids transiently affects bone marrow microenvironment, osteoblast and osteoclast formation, and bone mass in male offspring
Publisher: The Endocrine Society
Date: 28-02-2012
DOI: 10.1210/EN.2011-1917
Abstract: It is increasingly evident that micronutrient environment experienced before birth and in infancy is important for achieving optimal bone mass by adolescence and maintaining bone health. This study determined whether maternal supplementation with ω3-polyunsaturated fatty acids (n3FA) improved offspring bone growth and adult bone mass. Female rats were fed a diet containing 0.1% (control, n = 10) or 1% (n3FA, n = 11) docosahexanoic acid (DHA) during pregnancy and lactation. Offspring were weaned onto a control rat chow diet. Tibial growth plate and metaphysis structure, osteoblast/osteoclast density and differentiation, and gene expression were assessed in offspring at 3 wk (weaning), 6 wk (adolescent), and 3 months (adult). Maternal n3FA supplementation elevated offspring plasma n3FA levels at 3 and 6 wk. Although total growth plate heights were unaffected at any age, the resting zone thickness was increased in both male and female offspring at 3 wk. In n3FA males, but not females, bone trabecular number and thickness were increased at 3 wk but not other ages. The wk 3 n3FA males also exhibited an increased bone volume, an increased osteoblast but decreased osteoclast density, and lower expression of osteoclastogenic cytokines receptor activator of nuclear factor-κB ligand, TNF-α, and IL-6. No effects were seen at 6 wk or 3 months in either sex. Thus, perinatal n3FA supplementation is associated with increased bone formation, decreased resorption, and a higher bone mass in males, but not in females, at weaning these effects do not persist into adolescence and adulthood and are unlikely to produce lasting improvements in bone health.
Pre-treatment with insulin-like growth factor-I partially ameliorates 5-fluorouracil-induced intestinal mucositis in rats
Publisher: Elsevier BV
Date: 02-2005
DOI: 10.1016/J.GHIR.2004.12.002
Abstract: Insulin-like growth factor-I (IGF-I) has been demonstrated to enhance mucosal repair following intestinal damage induced by chemotherapeutic agents (intestinal mucositis). However, the potential for prophylactic IGF-I to protect the intestine remains undefined. We investigated the effects of IGF-I pre-treatment on chemotherapy-induced mucositis in rats. Male Sprague Dawley rats were treated for 7 days with 0 or 4.3mg/kg/day IGF-I delivered systemically via osmotic mini-pump. Rats received an intraperitoneal injection of 0 or 150 mg/kg 5-fluorouracil (5-FU) on day 7 and were killed 48 h later for assessment of intestinal damage and repair. Compared to normal controls, 5-FU decreased epithelial proliferation by 86%, concurrently increasing the incidence of apoptosis 87-fold, whilst decreasing small intestinal (SI) length by 14%, SI weight by 30% and total gut weight by 24%. 5-FU decreased villus height in the duodenum (23%), jejunum (20%) and ileum (30%) with crypt depths decreased by 31%, 27% and 33% in these gut regions. These effects were less profound in IGF-I pre-treated rats in which apoptosis was increased 48-fold, with SI length decreased by 7%, SI weight by 18% and total gut weight by 15% accompanied by decreases in villus height of 8% (duodenum), 14% (jejunum) and 21% (ileum), and crypt depth decreases of 23%, 16% and 17% for the same gut regions, compared to normal controls. We conclude that IGF-I pre-treatment only partially attenuates features of intestinal mucositis when assessed 48 h after 5-FU chemotherapy.
Heat shock protein-90 beta is expressed at the surface of multipotential mesenchymal precursor cells: Generation of a novel monoclonal antibody, STRO-4, with specificity for mesenchymal precursor cells from human and ovine tissues
Publisher: Mary Ann Liebert Inc
Date: 11-2009
Abstract: Mesenchymal stromal cells (MSCs) and their precursor cells (MPCs) can proliferate and differentiate into multiple mesodermal and some ectodermal and endodermal tissues. Culture-expanded MSCs are currently being evaluated as a possible cell therapy to replace/repair injured or diseased tissues. While a number of mAb reagents with specificity to human MSCs, including STRO-1, STRO-3 (BLK ALP), CD71 (SH2, SH3), CD106 (VCAM-1), CD166, and CD271, have facilitated the isolation of purified populations of human MSCs from primary tissues, few if any mAb reagents have been described that can be used to isolate equivalent cells from other species. This is of particular relevance when assessing the tissue regenerative efficacy of MSCs in large immunocompetent, preclinical animal models of disease. In light of this, we sought to generate novel monoclonal antibodies (mAb) with specific reactivity against a cell surface molecule that is expressed at high levels by MSCs from different species. Using CD106 (VCAM-1)-selected ovine MSCs as an immunogen, mAb-producing hybridomas were selected for their reactivity to both human and ovine MSCs. One such hybridoma, termed STRO-4, produced an IgG mAb that reacted with <5% of human and ovine bone marrow (BM) mononuclear cells. As a single selection reagent, STRO-4 mAb was able to enrich colony-forming fibroblasts (CFU-F) in both human and ovine BM by 16- and 8-folds, respectively. Cells isolated with STRO-4 exhibited reactivity with markers commonly associated with MSCs isolated by plastic adherence including CD29, CD44, and CD166. Moreover, when placed in inductive culture conditions in vitro, STRO-4(+) MSCs exhibited multilineage differentiation potential and were capable of forming a mineralized matrix, lipid-filled adipocytes, and chondrocytes capable of forming a glycosaminoglycan-rich matrix. Biochemical analysis revealed that STRO-4 identified the beta isoform of heat shock protein-90 (Hsp90beta). In addition to identifying an antibody reagent that identifies a highly conserved epitope expressed by MSCs from different species, our study also points to a potential role for Hsp90beta in MSC biology.
Regulation, bone growth defects, and potential treatments
Publisher: Bioscientifica
Date: 08-2014
DOI: 10.1530/JME-14-0165
A novel FGFR3-binding peptide inhibits FGFR3 signaling and reverses the lethal phenotype of mice mimicking human thanatophoric dysplasia.
Publisher: Oxford University Press (OUP)
Date: 26-09-2012
DOI: 10.1093/HMG/DDS390
Effects of TGF-α gene Knockout on epithelial cell kinetics and repair of methotrexate-induced damage in mouse small intestine
Publisher: Wiley
Date: 21-03-2002
DOI: 10.1002/JCP.10079
Abstract: While previous studies have indicated that exogenous TGF-alpha stimulates epithelial growth, maintenance, and repair of the gut, roles of endogenous TGF-alpha are less well-defined particularly in the small bowel. The current study examined effects of TGF-alpha knockout on adult small intestinal epithelial cell proliferation, migration, apoptosis, and damage/repair response after methotrexate treatment. Compared to normal mice, TGF-alpha gene knockout did not affect crypt cell production, mitosis position, migration, and apoptosis in non-injured intestine. RT-PCR gene expression analysis revealed presence of four out of six TGF-alpha related EGF family ligands in the normal intestine, suggesting a possible functional redundancy of the EGF family in maintenance of the intestine. Although TGF-alpha gene knockout did not significantly impair the overall mucosal repair in methotrexate-induced acute damage in the small intestine, it resulted in a higher apoptotic response in the early hours following methotrexate challenge, and a delayed and reduced crypt cell proliferation during repair. Consistently, after methotrexate challenge, intestinal TGF-alpha mRNA was found to be markedly upregulated in the early hours and during repair in the wild type, and there were similar profiles in the increased expression of all other ligands (except EGF) between the wild type and knockout intestines. Therefore, despite a possible functional redundancy among the EGF family ligands in the normal small intestine, TGF-alpha may play a role in modulating the early apoptotic events and in enhancing the subsequent reparative proliferative response in the methotrexate-damaged intestine.
Effects of Frequency and Acceleration Amplitude on Osteoblast Mechanical Vibration Responses: A Finite Element Study
Publisher: Hindawi Limited
Date: 2016
DOI: 10.1155/2016/2735091
Abstract: Bone cells are deformed according to mechanical stimulation they receive and their mechanical characteristics. However, how osteoblasts are affected by mechanical vibration frequency and acceleration litude remains unclear. By developing 3D osteoblast finite element (FE) models, this study investigated the effect of cell shapes on vibration characteristics and effect of acceleration (vibration intensity) on vibrational responses of cultured osteoblasts. Firstly, the developed FE models predicted natural frequencies of osteoblasts within 6.85–48.69 Hz. Then, three different levels of acceleration of base excitation were selected (0.5, 1, and 2 g) to simulate vibrational responses, and acceleration of base excitation was found to have no influence on natural frequencies of osteoblasts. However, vibration response values of displacement, stress, and strain increased with the increase of acceleration. Finally, stress and stress distributions of osteoblast models under 0.5 g acceleration in Z -direction were investigated further. It was revealed that resonance frequencies can be a monotonic function of cell height or bottom area when cell volumes and material properties were assumed as constants. These findings will be useful in understanding how forces are transferred and influence osteoblast mechanical responses during vibrations and in providing guidance for cell culture and external vibration loading in experimental and clinical osteogenesis studies.
Methotrexate Chemotherapy Causes Growth Impairments, Vitamin D Deficiency, Bone Loss, and Altered Intestinal Metabolism-Effects of Calcitriol Supplementation
Publisher: MDPI AG
Date: 11-06-2023
Prevention of Bone Growth Defects, Increased Bone Resorption and Marrow Adiposity with Folinic Acid in Rats Receiving Long-Term Methotrexate
Publisher: Public Library of Science (PLoS)
Date: 05-10-2012
Lack of effects of transforming growth factor-α gene knockout on peripheral nerve regeneration may result from compensatory mechanisms
Publisher: Elsevier BV
Date: 11-2001
Pulsed electromagnetic fields promote bone formation by activating the sAC–cAMP–PKA–CREB signaling pathway
Publisher: Wiley
Date: 08-2019
DOI: 10.1002/JCP.27098
Abstract: The application of pulsed electromagnetic fields (PEMFs) in the prevention and treatment of osteoporosis has long been an area of interest. However, the clinical application of PEMFs remains limited because of the poor understanding of the PEMF action mechanism. Here, we report that PEMFs promote bone formation by activating soluble adenylyl cyclase (sAC), cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), and cAMP response element‐binding protein (CREB) signaling pathways. First, it was found that 50 Hz 0.6 millitesla (mT) PEMFs promoted osteogenic differentiation of rat calvarial osteoblasts (ROBs), and that PEMFs activated cAMP–PKA–CREB signaling by increasing intracellular cAMP levels, facilitating phosphorylation of PKA and CREB, and inducing nuclear translocation of phosphorylated (p)‐CREB. Blocking the signaling by adenylate cyclase (AC) and PKA inhibitors both abolished the osteogenic effect of PEMFs. Second, expression of sAC isoform was found to be increased significantly by PEMF treatment. Blocking sAC using sAC‐specific inhibitor KH7 dramatically inhibited the osteogenic differentiation of ROBs. Finally, the peak bone mass of growing rats was significantly increased after 2 months of PEMF treatment with 90 min/day. The serum cAMP content, p‐PKA, and p‐CREB as well as the sAC protein expression levels were all increased significantly in femurs of treated rats. The current study indicated that PEMFs promote bone formation in vitro and in vivo by activating sAC–cAMP–PKA–CREB signaling pathway of osteoblasts directly or indirectly.
Maternal omega-3 supplementation increases fat mass in male and female rat offspring.
Publisher: Frontiers Media SA
Date: 2011
Roles of growth factors in chemotherapy-induced intestinal mucosal damage repair
Publisher: Bentham Science Publishers Ltd.
Date: 08-2003
Abstract: Chemotherapy agents induce apoptotic cell death and loss of cell proliferation in the intestinal crypt epithelium, resulting in intestinal mucosal damage called "mucositis". Small intestinal mucositis is characterized structurally by crypt loss and villus atrophy, and functionally by absorptive and barrier impairments. The increased use of chemotherapy in cancer treatment and the clinical importance of the intestinal mucositis as a common side effect have stimulated more active research into understanding the pathophysiology of intestinal mucositis and developing agents for preventing or treating this condition. Rodent studies have shown that, following the chemotherapy-induced initial apoptosis and loss of crypt cell proliferation, many different growth factors or their receptors are upregulated locally at the crypts, preceding or coinciding with the epithelial hyperproliferative repair response. Aiming to reduce crypt cell apoptotic sensitivity to cytotoxic chemotherapy and/or to enhance crypt epithelial proliferative repair, several exogenous growth factor treatments have been tested, either preclinically and/or clinically, and are showing promise for their efficacy or safety in preventing or treating chemotherapy-induced mucositis. These tested growth factors include keratinocyte growth factor, interleukin-11, transforming growth factor beta, milk-derived growth factor extract, macrophage/granulocyte colony stimulating factors, and glucagon-like peptide 2. Further research on the basic and discovery levels and subsequent translational studies are needed to understand more about chemotherapy-induced intestinal mucositis and to identify candidates of growth factors or other agents that will potentially prevent or treat chemotherapy-induced mucositis more effectively, specifically, safely, and practically in chemotherapy patients.
TGF-α Overexpression in Breast Cancer Bone Metastasis and Primary Lesions and TGF-α Enhancement of Expression of Procancer Metastasis Cytokines in Bone Marrow Mesenchymal Stem Cells
Publisher: Hindawi Limited
Date: 2018
DOI: 10.1155/2018/6565393
Abstract: Bone metastasis (BM) is the advanced complication of breast cancer, while bone marrow-derived mesenchymal stem cells (BMSCs) in the microenvironment unclearly contribute to cancer metastasis. This study investigated potential roles of transforming growth factor- (TGF-) α in the interaction between breast cancer and BMSCs in BM. Clinical cases of breast cancer with bone metastasis (BMBC), breast cancer without bone metastasis (Non-BM-BC), and benign fibroadenoma (Benign) were enlisted in a retrospective study. TGF- α was found obviously overexpressed in BM lesion of BMBC compared to primary lesion of both BMBC and Non-BM-BC ( P 0.01 ), and TGF- α was higher in primary lesion of both BMBC and Non-BM-BC ( P 0.01 ) than Benign group. Interestingly, TGF- α in nontumor tissues of both BMBC and Non-BM-BC was at a higher level than Benign group ( P 0.01 ), and numbers of macrophages in nontumor tissues of both BMBC and Non-BM-BC ( P 0.01 ) were higher than Benign group. Furthermore, in cultured human BMSCs, TGF- α stimulated production of procancer cytokines including IL-6, VEGF, FGF10, FGF17, and TGF- β 1 in a dose-dependent manner. Thus, TGF- α in BC could potentially be an important signal of carcinogenesis and metastasis. Macrophages in the nontumor tissue of BC may not be protective but could promote cancer metastasis.
Sinusoidal electromagnetic fields promote bone formation and inhibit bone resorption in rat femoral tissues in vitro
Publisher: Informa UK Limited
Date: 21-10-2016
DOI: 10.3109/15368378.2014.971958
Abstract: Effects of sinusoidal electromagnetic fields (SEMFs) on bone metabolism have not yet been well defined. The present study investigated SEMF effects on bone formation and resorption in rat femur bone tissues in vitro. Cultured femur diaphyseal (cortical bone) and metaphyseal (trabecular bone) tissues were treated with 50 Hz 1.8 mT SEMFs 1.5 h per day for up to 12 days and treatment effects on bone formation and resorption markers and associated gene expression were examined. Treatment with SEMFs caused a significant increase in alkaline phosphatase (ALP) activity and inhibited the tartrate-resistant acid phosphatase (TRACP) activity in the femoral diaphyseal or metaphyseal tissues. SEMFs also significantly increased levels of mRNA expression of osterix (OSX), insulin-like growth factor (IGF-1) and ALP in the bone tissues. SEMF treatment decreased glucose content and increased lactic acid contents in the culture conditioned medium. In addition, treatment with SEMFs decreased mRNA expression levels of bone resorption-related genes TRACP, macrophage colony stimulating factor (M-CSF) and cathepsin K (CTSK) in the cultured bone tissues. In conclusion, the current study demonstrated that treatment with 1.8 mT SEMFs at 1.5 h per day promoted bone formation, increased metabolism and inhibited resorption in both metaphyseal and diaphyseal bone tissues in vitro.
Methotrexate-induced bone marrow adiposity Is mitigated by folinic acid supplementation through the regulation of Wnt/?-catenin signalling
Publisher: Wiley
Date: 21-11-2015
DOI: 10.1002/JCP.24788
Abstract: Antimetabolite Methotrexate (MTX) is commonly used in childhood oncology. As a dihydrofolate reductase inhibitor it exerts its action through the reduction of cellular folate, thus its intensive use is associated with damage to soft tissues, bone marrow, and bone. In the clinic, MTX is administered with folinic acid (FA) supplementation to alleviate some of this soft tissue damage. However, whether and how FA alleviates damage to the bone and bone marrow requires further investigation. As the Wnt/β-catenin signalling pathway is critical for commitment and differentiation of mesenchymal stem cells down the osteogenic or adipogenic lineage, its deregulation has been found associated with increased marrow adiposity following MTX treatment. In order to elucidate whether FA supplementation prevents MTX-induced bone marrow adiposity by regulating Wnt/β-catenin signalling, young rats were given saline or 0.75 mg/kg MTX once daily for 5 days, receiving saline or 0.75 mg/kg FA 6 h after MTX. FA rescue alleviated the MTX-induced bone marrow adiposity, as well as inducing up-regulation of Wnt10b mRNA and β-catenin protein expression in the bone. Furthermore, FA blocked up-regulation of the secreted Wnt antagonist sFRP-1 mRNA expression. Moreover, secreted sFRP-1 protein in the bone marrow and its expression by osteoblasts and adipocytes was found increased following MTX treatment. This potentially indicates that sFRP-1 is a major regulator of defective Wnt/β-catenin signalling following MTX treatment. This study provides evidence that folate depletion caused by MTX chemotherapy results in increased bone marrow adiposity, and that FA rescue alleviates these defects by up-regulating Wnt/β-catenin signalling in the bone.
Regular Supplementation With Resveratrol Improves Bone Mineral Density in Postmenopausal Women: A Randomized, Placebo‐Controlled Trial
Publisher: Wiley
Date: 14-07-2020
DOI: 10.1002/JBMR.4115
Preclinical Studies on Mesenchymal Stem Cell-Based Therapy for Growth Plate Cartilage Injury Repair
Publisher: Hindawi Limited
Date: 2011
DOI: 10.4061/2011/570125
Abstract: In the last two decades, there has been a strong interest in searching for biological treatments for regeneration of injured growth plate cartilage and prevention of its bony repair. Various means have been tried, including implantation of chondrocytes, mesenchymal stem cell (MSC), together with exogenous growth factor and scaffolds, and gene therapy. However, with the lack of success with chondrocytes, more research has focussed on MSC-based treatments. In addition to circumvent limitations with MSC-based treatments (including cell harvest-associated morbidity, difficulties/time/cost involved in MSC isolation and ex vivo expansion, and potential disease transmission), mobilising endogenous MSCs to the growth plate injury site and enhancing in situ regeneration mechanisms would represent an alternative attractive approach. Further studies are required to investigate the potential particularly in large animal models or clinical setting of the ex vivo MSC approach and the feasibility of the endogenous MSC in situ approach in growth plate regeneration.
Cover Image, Volume 233, Number 7, July 2018
Publisher: Wiley
Date: 30-03-2018
DOI: 10.1002/JCP.26565
Methotrexate chemotherapy-induced damages in bone marrow sinusoids: An in vivo and in vitro study
Publisher: Wiley
Date: 14-09-2019
DOI: 10.1002/JCB.27589
Abstract: Chemotherapeutic agents are very well evident extrinsic stimuli for causing damage to endothelial cells. Methotrexate is an antimetabolite commonly used to treat solid tumours and paediatric cancers. However, studies on the effect(s) of methotrexate on bone marrow microvascular system are inadequate. In the current study, we observed a significant bone marrow microvascular dilation following methotrexate therapy in rats, accompanied by apoptosis induction in bone marrow sinusoidal endothelial cells, and followed by recovery of bone marrow sinusoids associated with increased proliferation of remaining bone marrow sinusoidal endothelial cells. Our in vitro studies revealed that methotrexate is cytotoxic for cultured sinusoidal endothelial cells and can also induce apoptosis which is associated with upregulation of expression ratio of Bax and Bcl‐2 genes and Bax/Bcl‐2 expression ratio. Furthermore, it was shown that methotrexate can negatively affect proliferation of cultured sinusoidal endothelial cells and also inhibit their abilities of migration and formation of microvessel like tubes. The data from this study indicates that methotrexate can cause significant bone marrow sinusoidal endothelium damage in vivo and induce apoptosis and inhibit proliferation, migration and tube‐forming abilities of sinusoidal endothelial cells in vitro.
Folinic acid attenuates methotrexate chemotherapy-induced damages on bone growth mechanisms and pools of bone marrow stromal cells
Publisher: Wiley
Date: 2007
DOI: 10.1002/JCP.21274
Abstract: Chemotherapy often induces bone growth defects in pediatric cancer patients yet the underlying cellular mechanisms remain unclear and currently no preventative treatments are available. Using an acute chemotherapy model in young rats with the commonly used antimetabolite methotrexate (MTX), this study investigated damaging effects of five once-daily MTX injections and potential protective effects of supplementary treatment with antidote folinic acid (FA) on cellular activities in the tibial growth plate, metaphysis, and bone marrow. MTX suppressed proliferation and induced apoptosis of chondrocytes, and reduced collagen-II expression and growth plate thickness. It reduced production of primary spongiosa bone, volume of secondary spongiosa bone, and proliferation of metaphyseal osteoblasts, preosteoblasts and bone marrow stromal cells, with the cellular activities being most severely damaged on day 9 and returning to or towards near normal levels by day 14. On the other hand, proliferation of marrow pericytes was increased early after MTX treatment and during repair. FA supplementation significantly suppressed chondrocyte apoptosis, preserved chondrocyte proliferation and expression of collagen-II, and attenuated damaging effects on production of calcified cartilage and primary bone. The supplementation also significantly reduced MTX effects on proliferation of metaphyseal osteoblastic cells and of bone marrow stromal cells, and enhanced pericyte proliferation. These observations suggest that FA supplementation effectively attenuates MTX damage on cellular activities in producing calcified cartilage and primary trabecular bone and on pools of osteoblastic cells and marrow stromal cells, and that it enhances proliferation of mesenchymal progenitor cells during bone/bone marrow recovery.
Characterisation and developmental potential of ovine bone marrow derived mesenchymal stem cells
Publisher: Wiley
Date: 05-2009
DOI: 10.1002/JCP.21670
Abstract: Since discovery, significant interest has been generated in the potential application of mesenchymal stem cells or multipotential stromal cells (MSC) for tissue regeneration and repair, due to their proliferative and multipotential capabilities. Although the sheep is often used as a large animal model for translating potential therapies for musculoskeletal injury and repair, the characteristics of MSC from ovine bone marrow have been inadequately described. Histological and gene expression studies have previously shown that ovine MSC share similar properties with human and rodents MSC, including their capacity for clonogenic growth and multiple stromal lineage differentiation. In the present study, ovine bone marrow derived MSCs positively express cell surface markers associated with MSC such as CD29, CD44 and CD166, and lacked expression of CD14, CD31 and CD45. Under serum-deprived conditions, proliferation of MSC occurred in response to EGF, PDGF, FGF-2, IGF-1 and most significantly TGF-alpha. While subcutaneous transplantation of ovine MSC in association with a ceramic HA/TCP carrier into immunocomprimised mice resulted in ectopic osteogenesis, adipogenesis and haematopoietic-support activity, transplantation of these cells within a gelatin sponge displayed partial chondrogenesis. The comprehensive characterisation of ovine MSC described herein provides important information for future translational studies involving ovine MSC.
Preconditioning selective ventral root injury promotes plasticity of ascending sensory neurons in the injured spinal cord of adult rats - Possible roles of brain-derived neurotrophic factor, TrkB and p75 neurotrophin receptor
Publisher: Wiley
Date: 05-10-2009
DOI: 10.1111/J.1460-9568.2009.06920.X
Abstract: Preconditioning sciatic nerve injury enhances axonal regeneration of ascending sensory neurons after spinal cord injury. A key question is whether direct injury of sensory nerves is necessary for the enhanced regeneration. The lumbar 5 ventral root transection (L5 VRT) model, a model of selective motor nerve injury, provides a useful tool to address this question. Here we examined the effects of a preconditioning L5 VRT on the regeneration after a subsequent dorsal column transection (DCT) in adult Sprague-Dawley rats. We found that L5 VRT 1 week before DCT increased the number of Fast Blue (FB)-labeled neurons in the L5 dorsal root ganglia (DRG) and promoted sprouting/regenerating axons to grow into the glial scar. L5 VRT also induced a dramatic upregulation of expression of brain-derived neurotrophic factor (BDNF) in the preconditioned DRG and in the injured spinal cord. Moreover, almost all of the FB-labeled sprouting/regenerating neurons expressed BDNF, and approximately 55% of these neurons were surrounded by p75 neurotrophin receptor-positive glial cells. This combined injury led to an increase in the number of BDNF- and TrkB-immunoreactive nerve fibers in the dorsal column caudal to the lesion site. Taken together, these findings demonstrate that L5 VRT promotes sprouting/regeneration of ascending sensory neurons, indicating that sensory axotomy may not be essential for the plasticity of injured dorsal column axons. Thus, the sensory neurons could be preprimed in the regenerative milieu of Wallerian degeneration and neuroinflammation, which might alter the expression of neurotrophic factors and their receptors, facilitating sprouting/regeneration of ascending sensory neurons.
Different Electromagnetic Field Waveforms Have Different Effects on Proliferation, Differentiation and Mineralization of Osteoblasts InVitro
Publisher: Wiley
Date: 17-06-2014
DOI: 10.1002/BEM.21794
Abstract: Noninvasive electromagnetic fields (EMFs) have been known to be able to improve bone health however, their optimal application parameters and action mechanisms remain unclear. This study compared the effects of different forms of EMFs (sinusoidal, triangular, square, and serrated, all set at 50 Hz frequency and 1.8 mT intensity) on proliferation, differentiation and mineralization of rat calvarial osteoblasts. Square EMFs stimulated osteoblast proliferation but sinusoidal EMFs inhibited it. Sinusoidal and triangular EMFs produced significantly greater alkaline phosphatase (ALP) activity, ALP staining areas, calcium deposition, mineralized nodule areas, and mRNA expression of Runx-2, osteoprotegerin and insulin-like growth factor-I than square and serrated EMFs (P < 0.01). Triangular EMFs had a greater effect than sinusoidal EMFs on every indices except for Runx-2 mRNA expression (P < 0.05). These results indicated that while square EMFs promoted proliferation and had no effect on the differentiation of osteoblasts, sinusoidal EMFs inhibited proliferation but enhanced osteogenic differentiation. Triangular EMFs did not affect cell proliferation but induced the strongest osteogenic activity among the four waveforms of EMFs. Thus, the effects of EMFs on proliferation and differentiation of osteoblasts in vitro were dependent on their waveforms.
A hybrid platform for three-dimensional printing of bone scaffold by combining thermal-extrusion and electrospinning methods
Publisher: Springer Science and Business Media LLC
Date: 11-02-2019
Leptin accelerates the pathogenesis of heterotopic ossification in rat tendon tissues via mTORC1 signaling
Publisher: Wiley
Date: 05-06-2017
DOI: 10.1002/JCP.25955
Abstract: Leptin, an adipocyte‐derived cytokine associated with bone metabolism, is believed to play a critical role in the pathogenesis of heterotopic ossification (HO). The effect and underlying action mechanism of leptin were investigated on osteogenic differentiation of tendon‐derived stem cells (TDSCs) in vitro and the HO formation in rat tendons. Isolated rat TDSCs were treated with various concentrations of leptin in the presence or absence of mTORC1 signaling specific inhibitor rapamycin in vitro. A rat model with Achilles tenotomy was employed to evaluate the effect of leptin on HO formation together with or without rapamycin treatment. In vitro studies with TDSCs showed that leptin increased the expression of osteogenic biomarkers (alkaline phosphatase, runt‐related transcription factor 2, osterix, osteocalcin) and enhanced mineralization of TDSCs via activating the mTORC1 signal pathway (as indicated by phosphorylation of p70 ribosomal S6 kinase 1 and p70 ribosomal S6). However, mTORC1 signaling blockade with rapamycin treatment suppressed leptin‐induced osteogenic differentiation and mineralization. In vivo studies showed that leptin promoted HO formation in the Achilles tendon after tenotomy, and rapamycin treatment blocked leptin‐induced HO formation. In conclusion, leptin can promote TDSC osteogenic differentiation and heterotopic bone formation via mTORC1 signaling in both vitro and vivo model, which provides a new potential therapeutic target for HO prevention.
Research Progress on Nanomaterials for Tissue Engineering in Oral Diseases
Publisher: MDPI AG
Date: 08-2023
DOI: 10.3390/JFB14080404
Abstract: Due to their superior antibacterial properties, biocompatibility and high conductivity, nanomaterials have shown a broad prospect in the biomedical field and have been widely used in the prevention and treatment of oral diseases. Also due to their small particle sizes and biodegradability, nanomaterials can provide solutions for tissue engineering, especially for oral tissue rehabilitation and regeneration. At present, research on nanomaterials in the field of dentistry focuses on the biological effects of various types of nanomaterials on different oral diseases and tissue engineering applications. In the current review, we have summarized the biological effects of nanoparticles on oral diseases, their potential action mechanisms and influencing factors. We have focused on the opportunities and challenges to various nanomaterial therapy strategies, with specific emphasis on overcoming the challenges through the development of biocompatible and smart nanomaterials. This review will provide references for potential clinical applications of novel nanomaterials in the field of oral medicine for the prevention, diagnosis and treatment of oral diseases.
Contact damage failure analyses of fretting wear behavior of the metal stem titanium alloy-bone cement interface
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.JMBBM.2015.06.025
Abstract: Although cemented titanium alloy is not favored currently in the Western world for its poor clinical and radiography outcomes, its lower modulus of elasticity and good biocompatibility are instrumental for its ability supporting and transforming physical load, and it is more suitable for usage in Chinese and Japanese populations due to their lower body weights and unique femoral characteristics. Through various friction tests of different cycles, loads and conditions and by examining fretting hysteresis loops, fatigue process curves and wear surfaces, the current study investigated fretting wear characteristics and wear mechanism of titanium alloy stem-bone cement interface. It was found that the combination of loads and displacement affected the wear quantity. Friction coefficient, which was in an inverse relationship to load under the same litude, was proportional to litudes under the same load. Additionally, calf serum was found to both lubricate and erode the wear interface. Moreover, cement fatigue contact areas appeared black/oxidative in dry and gruel in 25% calf serum. Fatigue scratches were detected within contact areas, and wear scars were found on cement and titanium surfaces, which were concave-shaped and ring concave/ convex-shaped, respectively. The coupling of thermoplastic effect and minimal torque damage has been proposed to be the major reason of contact damage. These data will be important for further studies analyzing metal-cement interface failure performance and solving interface friction and wear debris production issues.
HYDROXYMETHYL FURFURAL IN CHINESE HERBAL MEDICINES: ITS FORMATION, PRESENCE, METABOLISM, BIOACTIVITIES AND IMPLICATIONS
Publisher: African Journals Online (AJOL)
Date: 13-04-2015
Microarray expression analysis of genes and pathways involved in growth plate cartilage injury responses and bony repair
Publisher: Elsevier BV
Date: 05-2012
DOI: 10.1016/J.BONE.2012.02.013
Abstract: The injured growth plate cartilage is often repaired by a bone bridge which causes bone growth deformities. Whilst previous studies have identified sequential inflammatory, fibrogenic, osteogenic and bone remodelling responses involved in the repair process, the molecular pathways which regulated these cellular events remain unknown. In a rat growth plate injury model, tissue from the injury site was collected across the time-course of bone bridge formation using laser capture microdissection and was subjected to Affymetrix microarray gene expression analysis. Real Time PCR and immunohistochemical analyses were used to confirm changes in levels of expression of some genes identified in microarray. Four major functional groupings of differentially expressed genes with known roles in skeletal development were identified across the time-course of bone bridge formation, including Wnt signalling (SFRP1, SFRP4, β-catenin, Csnk2a1, Tcf7, Lef1, Fzd1, Fzd2, Wisp1 and Cpz), BMP signalling (BMP-2, BMP-6, BMP-7, Chrd, Chrdl2 and Id1), osteoblast differentiation (BMP-2, BMP-6, Chrd, Hgn, Spp1, Axin2, β-catenin, Bglap2) and skeletal development (Chrd, Mmp9, BMP-1, BMP-6, Spp1, Fgfr1 and Traf6). These studies provide insight into the molecular pathways which act cooperatively to regulate bone formation following growth plate cartilage injury and highlight potential therapeutic targets to limit bone bridge formation.
Expression of Bone Morphogenic Proteins and Receptors at the Injured Growth Plate Cartilage in Young Rats
Publisher: SAGE Publications
Date: 17-04-2006
Abstract: The injured growth plate cartilage is often repaired by bony tissue, resulting in impaired bone growth in children. Bone morphogenic proteins (BMPs) are important for bone fracture repair, and as a step to characterize potential involvement of BMPs in bony repair of injured growth plate, expression of BMPs and receptors (BMP-R) was examined by quantitative RT-PCR and immunohistochemistry in rat injured tibial growth plate. During the inflammatory response on day 1, slightly increased expression of BMP-3, BMP-4, BMP-R1a, and BMP-R2 was observed, with immunostaining seen among inflammatory cells at the injury site. During mesenchymal infiltration and osteogenic responses on days 3-14, moderately increased expression of BMP-2, −3, −4, −7, and BMP-R1a was found, with immunostaining observed among infiltrated mesenchymal cells and differentiated osteoblasts lining bony trabeculae. During maturation phase on days 14-25, only BMP-7 was seen upregulated slightly and was localized in osteoblasts and marrow cells at the injury site. The temporospatial expression of BMPs and receptors at the injured growth plate suggests potential involvement of BMP-3 and −4 in regulating the inflammatory response or as its mediators in modulating downstream events, and BMP-2, −3, −4, and −7 in the fibrogenic and osteogenic responses, and BMP-7 in bone remodeling at the injured growth plate.
Roles of COX-2 and iNOS in the bony repair of the injured growth plate cartilage
Publisher: Wiley
Date: 2006
DOI: 10.1002/JCB.20905
Abstract: Growth plate injuries often lead to bone growth defects, which primarily occur due to bony repair at injury sites. Bony repair is preceded by an injury-induced inflammatory response, which could play a role in regulating the repair process. Here, roles of two inflammatory mediators, cyclo-oxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS), in the injury responses were analysed by examining their gene expression and effects of blocking their activities, respectively, with celecoxib and aminoguanidine during 2 days prior to and until 7 days after injury in a rat tibial growth plate injury model. Quantitative RT-PCR assays revealed upregulated expression of COX-2 on days 1 and 4 and iNOS on day 1. Histological analysis of injury sites revealed significant reductions in inflammatory infiltrate (particularly neutrophils) on day 1 in treated groups compared to saline control. While bony tissue proportions at injury sites were unaffected by either treatment, mesenchymal tissue proportions were larger but cartilaginous tissue proportions were smaller on day 8 (though statistically insignificant), and bone remodelling appeared delayed with a smaller bone marrow proportion on day 14 in both treatment groups. These findings suggest that COX-2 and iNOS mediate injury-induced inflammatory response, and may play a role in enhancing mesenchymal cell differentiation to cartilaginous cells and in promoting bone remodelling during bony repair of growth plate injury sites. Furthermore, increased expression of cartilage-related (collagen-2, collagen-10, SOX-9) and bone-related molecules (osteocalcin, cbfalpha-1) suggest involvement of both endochondral and direct bone formation mechanisms during bony repair.
Mechanical unloading reduces microtubule actin crosslinking factor 1 expression to inhibit β‐catenin signaling and osteoblast proliferation
Publisher: Wiley
Date: 23-01-2018
DOI: 10.1002/JCP.26374
Abstract: Mechanical unloading was considered a major threat to bone homeostasis, and has been shown to decrease osteoblast proliferation although the underlying mechanism is unclear. Microtubule actin crosslinking factor 1 (MACF1) is a cytoskeletal protein that regulates cellular processes and Wnt/β‐catenin pathway, an essential signaling pathway for osteoblasts. However, the relationship between MACF1 expression and mechanical unloading, and the function and the associated mechanisms of MACF1 in regulating osteoblast proliferation are unclear. This study investigated effects of mechanical unloading on MACF1 expression levels in cultured MC3T3‐E1 osteoblastic cells and in femurs of mice with hind limb unloading and it also examined the role and potential action mechanisms of MACF1 in osteoblast proliferation in MACF1‐knockdown, overexpressed or control MC3T3‐E1 cells treated with or without the mechanical unloading condition. Results showed that the mechanical unloading condition inhibited osteoblast proliferation and MACF1 expression in MC3T3‐E1 osteoblastic cells and mouse femurs. MACF1 knockdown decreased osteoblast proliferation, while MACF1 overexpression increased it. The inhibitory effect of mechanical unloading on osteoblast proliferation also changed with MACF1 expression levels. Furthermore, MACF1 was found to enhance β‐catenin expression and activity, and mechanical unloading decreased β‐catenin expression through MACF1. Moreover, β‐catenin was found an important regulator of osteoblast proliferation, as its preservation by treatment with its agonist lithium attenuated the inhibitory effects of MACF1‐knockdown or mechanical unloading on osteoblast proliferation. Taken together, mechanical unloading decreases MACF1 expression, and MACF1 up‐regulates osteoblast proliferation through enhancing β‐catenin signaling. This study has thus provided a mechanism for mechanical unloading‐induced inhibited osteoblast proliferation.
Endogenous BDNF is required for myelination and regeneration of injured sciatic nerve in rodents
Publisher: Wiley
Date: 12-2000
Therapeutic targeting notch2 protects bone micro-vasculatures from methotrexate chemotherapy-induced adverse effects in rats
Publisher: MDPI AG
Date: 02-08-2022
Abstract: Intensive cancer chemotherapy is well known to cause bone vasculature disfunction and damage, but the mechanism is poorly understood and there is a lack of treatment. Using a rat model of methotrexate (MTX) chemotherapy (five once-daily dosses at 0.75 mg/kg), this study investigated the roles of the Notch2 signalling pathway in MTX chemotherapy-induced bone micro-vasculature impairment. Gene expression, histological and micro-computed tomography (micro-CT) analyses revealed that MTX-induced micro-vasculature dilation and regression is associated with the induction of Notch2 activity in endothelial cells and increased production of inflammatory cytokine tumour necrosis factor alpha (TNFα) from osteoblasts (bone forming cells) and bone marrow cells. Blockade of Notch2 by a neutralising antibody ameliorated MTX adverse effects on bone micro-vasculature, both directly by supressing Notch2 signalling in endothelial cells and indirectly via reducing TNFα production. Furthermore, in vitro studies using rat bone marrow-derived endothelial cell revealed that MTX treatment induces Notch2/Hey1 pathway and negatively affects their ability in migration and tube formation, and Notch2 blockade can partially protect endothelial cell functions from MTX damage.
Pulsed electromagnetic fields stimulate osteogenic differentiation and maturation of osteoblasts by upregulating the expression of BMPRII localized at the base of primary cilium
Publisher: Elsevier BV
Date: 12-2016
DOI: 10.1016/J.BONE.2016.09.008
Abstract: Pulsed electromagnetic fields (PEMFs) have been considered as a potential candidate for the prevention and treatment of osteoporosis, however, the mechanism of its action is still elusive. We have previously reported that 50Hz 0.6mT PEMFs stimulate osteoblastic differentiation and mineralization in a primary cilium- dependent manner, but did not know the reason. In the current study, we found that the PEMFs promoted osteogenic differentiation and maturation of rat calvarial osteoblasts (ROBs) by activating bone morphogenetic protein BMP-Smad1/5/8 signaling on the condition that primary cilia were normal. Further studies revealed that BMPRII, the primary binding receptor of BMP ligand, was readily and strongly upregulated by PEMF treatment and localized at the bases of primary cilia. Abrogation of primary cilia with small interfering RNA sequence targeting IFT88 abolished the PEMF-induced upregulation of BMPRII and its ciliary localization. Knockdown of BMPRII expression level with RNA interference had no effects on primary cilia but significantly decreased the promoting effect of PEMFs on osteoblastic differentiation and maturation. These results indicated that PEMFs stimulate osteogenic differentiation and maturation of osteoblast by primary cilium-mediated upregulation of BMPRII expression and subsequently activation of BMP-Smad1/5/8 signaling, and that BMPRII is the key component linking primary cilium and BMP-Smad1/5/8 pathway. This study has thus revealed the molecular mechanism for the osteogenic effect of PEMFs.
Distribution of neurturin mRNA and immunoreactivity in the peripheral tissues of adult rats
Publisher: Elsevier BV
Date: 07-1999
DOI: 10.1016/S0006-8993(99)01590-5
Abstract: Neurturin (NTN) is a recently discovered neurotrophic factor related to glial cell line-derived neurotrophic factor (GDNF) and has a wide spectrum of biological roles in different types of neurons in the central and peripheral nervous systems. However, information on its expression in peripheral tissues has been limited, and there is no information on its peptide distribution. As a step to examine its role and action mechanisms in neuronal and non-neuronal cells in the periphery, the present study investigated the distribution patterns of its mRNA and peptide in some major peripheral organs of adult rats by in situ hybridization and immunohistochemistry. A widespread expression of NTN mRNA was found in the selected organs of various systems, with a high level in pituitary intermediate lobe, intestine, salivary gland, and testis, and a moderate level in ovary, adrenal gland, kidney, thyroid, and spleen. NTN peptide was also present in the peripheral organs studied, with its distribution corresponding to that of mRNA. In conclusion, NTN is expressed widely in many regionally well-defined cellular systems in various peripheral tissues, suggesting that NTN may act as a target-derived neurotrophic factor for innervating neurons and may have maintenance functions in non-neuronal cells of these adult organs.
Upregulation of brain-derived neurotrophic factor in the sensory pathway by selective motor nerve injury in adult rats
Publisher: Springer Science and Business Media LLC
Date: 12-2006
DOI: 10.1007/BF03033317
A study on protective performance of bullet-proof helmet under impact loading
Publisher: JVE International Ltd.
Date: 30-06-2016
Abstract: A large number of brain injuries and casualties can be caused by the impact of bullets on the bullet-proof helmets, for which the underlying mechanisms are unclear and are likely to be complex. In the current study, an American advanced combat helmet was scanned to obtain 3-dimensional (3D) geometric information, from which a 3D finite element (FE) model of a ballistic helmet was developed. With this model, FE simulation was conducted and the results were compared with and verified by data from a ballistic test and a FE simulation study previously reported. Furthermore, the protective performance of the ballistic helmet was investigated using the FE model. The verification results show that the FE model of this ballistic helmet is effective, and data from the current study should be useful in providing theoretical guidance in the design of ballistic helmets.
Injured primary sensory neurons switch phenotype for brain-derived neurotrophic factor in the rat
Publisher: Elsevier BV
Date: 06-1999
DOI: 10.1016/S0306-4522(99)00027-5
Abstract: Peripheral nerve injury results in plastic changes in the dorsal root ganglia and spinal cord, and is often complicated with neuropathic pain. The mechanisms underlying these changes are not known. We have now investigated the expression of brain-derived neurotrophic factor in the dorsal root ganglia with histochemical and biochemical methods following sciatic nerve lesion in the rat. The percentage of neurons immunoreactive for brain-derived neurotrophic factor in the ipsilateral dorsal root ganglia was significantly increased as early as 24 h after the nerve lesion and the increase lasted for at least two weeks. The level of brain-derived neurotrophic factor messenger RNA was also significantly increased in the ipsibut not contralateral dorsal root ganglia. Both neurons and satellite cells in the lesioned dorsal root ganglia synthesized brain-derived neurotrophic factor messenger RNA after the nerve lesion. There was a dramatic shift in size distribution of positive neurons towards large sizes seven days after sciatic nerve lesion. Morphometric analysis and retrograde tracing studies showed that no injured neurons smaller than 600 microm2 were immunoreactive for brain-derived neurotrophic factor, whereas the majority of large injured neurons were immunoreactive in the ipsilateral dorsal root ganglia seven days postlesion. The brain-derived neurotrophic factor-immunoreactive nerve terminals in the ipsilateral spinal cord were reduced in the central region of lamina II, but increased in more medial regions or deeper into laminae III/IV. These studies indicate that sciatic nerve injury results in a differential regulation of brain-derived neurotrophic factor in different subpopulations of sensory neurons in the dorsal root ganglia. Small neurons switched off their normal synthesis of brain-derived neurotrophic factor, whereas larger ones switched to a brain-derived neurotrophic factor phenotype. The phenotypic switch may have functional implications in neuronal plasticity and generation of neuropathic pain after nerve injury.
Supplementation with Fish Oil and Genistein, Individually or in Combination, Protects Bone against the Adverse Effects of Methotrexate Chemotherapy in Rats
Publisher: Public Library of Science (PLoS)
Date: 12-08-2013
Associations between the cyclooxygenase‐2 expression in circulating tumor cells and the clinicopathological features of patients with colorectal cancer
Publisher: Wiley
Date: 27-09-2018
DOI: 10.1002/JCB.27768
Abstract: While previous studies have shown that the number of circulating tumor cells (CTCs) alone is not sufficient to reflect tumor progression and that cyclooxygenase‐2 (COX‐2) expression is correlated with colorectal cancer (CRC) metastasis, COX‐2 expression status and its potential functions in CTCs of CRC patients are unknown. Here, epithelial‐mesenchymal transition (EMT) phenotype‐based subsets of CTCs and the COX‐2 expression status in CTCs were identified and their potential clinical values were assessed in 91 CRC patients. CTCs were enumerated in peripheral blood and subsets of CTCs (epithelial [eCTCs], mesenchymal [mCTCs], and biophenotypic [bCTCs]) and the COX‐2 expression status were determined using the RNA in situ hybridization method. CTCs were detected in 80.2% (73 of 91) patients. Neither the total CTC nor eCTC numbers were found to significantly associate with any of the clinicopathological features. However, the number of mCTCs was significantly associated with distance metastasis ( P = 0.035) and had a trend of being associated with lymph node metastasis ( P = 0.055). Among the 73 patients enrolled for evaluating COX‐2 expression, 52.5% (38 of 73) were found to express COX‐2 in CTCs, and COX‐2 expression in CTCs was not found to associate with the clinicopathological factors. However, COX‐2 expression in mCTCs tended to have a higher rate in patients with metastasis compared with those without metastasis (72.0% vs 42.8% P = 0.072). Furthermore, COX‐2 expression and mCTC marker expression correlated positively ( R = 0.287 P = 0.017). Further studies are required to investigate the clinical value of the expression of COX‐2 in mCTCs, especially in CRC patients with the advanced tumor stage and distant metastasis.
miR-542-3p attenuates bone loss and marrow adiposity following methotrexate treatment by targeting sFRP-1 and smurf2
Publisher: MDPI AG
Date: 12-10-2021
Abstract: Intensive methotrexate (MTX) treatment for childhood malignancies decreases osteogenesis but increases adipogenesis from the bone marrow stromal cells (BMSCs), resulting in bone loss and bone marrow adiposity. However, the underlying mechanisms are unclear. While microRNAs (miRNAs) have emerged as bone homeostasis regulators and miR-542-3p was recently shown to regulate osteogenesis in a bone loss context, the role of miR-542-3p in regulating osteogenesis and adipogenesis balance is not clear. Herein, in a rat MTX treatment-induced bone loss model, miR-542-3p was found significantly downregulated during the period of bone loss and marrow adiposity. Following target prediction, network construction, and functional annotation/ enrichment analyses, luciferase assays confirmed sFRP-1 and Smurf2 as the direct targets of miR-542-3p. miRNA-542-3p overexpression suppressed sFRP-1 and Smurf2 expression post-transcriptionally. Using in vitro models, miR-542-3p treatment stimulated osteogenesis but attenuated adipogenesis following MTX treatment. Subsequent signalling analyses revealed that miR-542-3p influences Wnt/β-catenin and TGF-β signalling pathways in osteoblastic cells. Our findings suggest that MTX treatment-induced bone loss and marrow adiposity could be molecularly linked to miR-542-3p pathways. Our results also indicate that miR-542-3p might be a therapeutic target for preserving bone and attenuating marrow fat formation during/after MTX chemotherapy.
Neuronal-glial differential expression of TGF-α and its receptor in the dorsal root ganglia in response to sciatic nerve lesion
Publisher: Elsevier BV
Date: 06-1999
Abstract: Injury to peripheral nerves often results in structural and functional changes in the dorsal root ganglia (DRG). Although the mechanisms underlying these changes remain largely unknown, satellite cell activation and up-regulation of several neurotrophic factors in the DRG occur in response to the nerve lesion, modulating the plasticity of affected neurons. To investigate potential roles of transforming growth factor alpha (TGF-alpha) in these plastic changes in the DRG following a sciatic nerve transection, here we examined the expression in DRGs of TGF-alpha and its receptor (EGF receptor), molecules known to be mitogenic to glia and Schwann cells and to be neurotrophic for some differentiated neurons. In the normal DRGs, TGF-alpha and its receptor are expressed mainly in small neurons and satellite cells surrounding some large or medium-sized neurons as determined by immunohistochemistry and in situ hybridization. In response to sciatic nerve lesion, there was a marked and differential up-regulation of TGF-alpha and EGF receptor expression within DRG, evident as early as 24 h after lesion and lasting for at least 14 days. While the up-regulated TGF-alpha was localized mainly on satellite cells in the ipsilateral and contralateral DRGs, EGF receptor up-regulation was mainly neuronal (with the expression expanding to include all neurons) in the ipsilateral DRGs, but mainly glial in the contralateral DRGs. These changes in TGF-alpha and its receptor expression suggest that TGF-alpha may play a role in the satellite cell proliferation and/or activation as well as in neuronal survival after nerve lesion.
Dynamic analyses of osteoblast vibrational responses: a finite element viscoelastic model
Publisher: JVE International Ltd.
Date: 15-11-2016
Abstract: Mechanotransduction is an important process that influences bone remodeling and maintains viability of bone cells. To understand the effect of the vibrational mechanical stimulation on biomechanic responses of bone cells, a viscoelastic osteoblast finite element (FE) model was developed. Firstly, the mode shapes and natural frequencies of a spreading osteoblast were assessed using the FE modal analysis. The osteoblast FE model predicted the natural frequencies of osteoblasts (within the range about 19.99-34.48 Hz). Then, the effect of acceleration on the vibrational responses of in-vitro cultured osteoblasts was investigated. Three different accelerations of base excitation were selected (0.15 g , 0.3 g and 0.5 g , where g = 9.8 m/s 2 ) and the vibrational responses (displacement, strain and stress) of osteoblasts were simulated. It was found that values of displacement, strain and stress increase with the increase of base excitation acceleration. In addition, the response values in Z -direction are much higher than those in the other directions ( X , Y -direction) for the same base excitation acceleration. These findings will provide useful information to understand how vibrational mechanical stimulus influences bone cells and provide guidance for in vitro cell culture and experimental research and ultimately clinical treatment using the external vibrating loading.
Pathobiology and Prevention of Cancer Chemotherapy-Induced Bone Growth Arrest, Bone Loss, and Osteonecrosis
Publisher: Bentham Science Publishers Ltd.
Date: 03-2011
DOI: 10.2174/156652411794859223
Abstract: Cancer chemotherapy has been recognized as one severe risk factor that influences bone growth and bone mass accumulation during childhood and adolescence. This article reviews on the importance of this clinical issue, current understanding of the underlying mechanisms for the skeletal defects and potential preventative strategies. Both clinical and basic studies that appeared from 1990 to 2010 were reviewed for bone defects (growth arrest, bone loss, osteonecrosis, and/or fractures) caused by paediatric cancer chemotherapy. As chemotherapy has become more intensive and achieved greater success in treating paediatric malignancies, skeletal complications such as bone growth arrest, low bone mass, osteonecrosis, and fractures during and/or after chemotherapy have become a problem for some cancer patients and survivors particularly those that have received high dose glucocorticoids and methotrexate. While chemotherapy-induced skeletal defects are likely multi-factorial, recent studies suggest that different chemotherapeutic agents can directly impair the activity of the growth plate and metaphysis (the two major components of the bone growth unit) through different mechanisms, and can alter bone modeling/remodeling processes via their actions on bone formation cells (osteoblasts), bone resorption cells (osteoclasts) and bone "maintenance" cells (osteocytes). Intensive use of multi-agent chemotherapy can cause growth arrest, low bone mass, fractures, and/or osteonecrosis in some paediatric patients. While there are currently no specific strategies for protecting bone growth during childhood cancer chemotherapy, regular BMD monitoring and exercise are have been recommended, and possible adjuvant treatments could include calcium/vitamin D, antioxidants, bisphosphonates, resveratrol, and/or folinic acid.
Icariin induces osteoblast differentiation and mineralization without dexamethasone in vitro
Publisher: Georg Thieme Verlag KG
Date: 26-09-2013
Abstract: An effective method for preventing bone loss is by promoting osteoblast differentiation and bone formation. While dexamethasone has been routinely used as a classical inducer for osteoblast differentiation, limitations have been observed with its usage, including its varied effects on expression of osteoblast genes in different species and its potentials in suppressing osteoblastic differentiation and mineralization. In this study, we assessed the ability of flavonoid icariin in enhancing differentiation and mineralization of cultured rat primary osteoblasts in the absence of dexamethasone. It was found that, compared to the non-stimulated control, icariin at 10(-5) M produced a higher alkaline phosphatase activity, more and larger areas of alkaline phosphatase-positive colonies (CFU-FALP) and mineralized nodules, more osteocalcin secretion and calcium deposition, higher levels of mRNA expression of alkaline phosphatase, osteoblastic transcription factors osterix and runt-related transcription factor 2, and collagen 1α, higher levels of protein expression of collagen 1α, alkaline phosphatese, osterix, and runt-related transcription factor 2. In addition, icariin at 10(-5) M was always more potent than dexamethasone at its optimal concentration of 10(-8) M on the above osteoblast differentiation and mineralization markers. Taken together, our studies demonstrated that icariin has a pronounced ability in promoting osteoblast differentiation in vitro in the absence of dexamethasone.
Fibroblast Growth Factor Receptor 3 Deficiency Does Not Impair the Osteoanabolic Action of Parathyroid Hormone on Mice.
Publisher: Ivyspring International Publisher
Date: 2016
DOI: 10.7150/IJBS.14077
The immuno‐reactivity of polypseudorotaxane functionalized magnetic CDMNP‐PEG‐CD nanoparticles
Publisher: Wiley
Date: 19-11-2020
DOI: 10.1111/JCMM.16109
Studies on T‐cell receptors involved in experimental autoimmune encephalomyelitis using the complementary peptide recognition approach
Publisher: Wiley
Date: 08-1995
Abstract: Based upon Blalock's complementary recognition approach, a complementary or antisense peptide (CP) was designed to the experimental autoimmune encephalomyelitis (EAE) epitope peptide, rat myelin basic protein (MBP) peptide 72-82. This peptide (EAE CP) was shown to have some sequence similarities to T-cell receptors (TCR) and MHC II molecules in a sequence homology search. Solid-phase binding assays demonstrated specific and high affinity binding (3 and 4 microM) between the EAE CP and the rat and guinea pig EAE epitope peptides (Rt72-82 and Gp69-82), respectively. This EAE CP was also found to be immunogenic in rats in an ear swelling test for delayed type hypersensitivity (DTH) reactions and an ELISA for antibody responses. However, a rabbit antibody generated to EAE CP was shown to be unable to stain the V beta 8+ EAE susceptible T-cells in immunofluorescence analyses. This EAE CP was also used in attempts to down-regulate EAE and the results showed that prior immunization with EAE CP in complete Freund's adjuvant could not prevent the Lewis rats from developing EAE. Although the data on sense-antisense peptide interaction were positive and the EAE CP was immunogenic, the inability of EAE CP to regulate EAE indicates that the CP approach may not be generally applicable.
Erratum: Different electromagnetic field waveforms have different effects on proliferation, differentiation and mineralization of osteoblasts in vitro
Publisher: Wiley
Date: 26-10-2014
DOI: 10.1002/BEM.21826
Fish oil in comparison to folinic acid for protection against adverse effects of methotrexate chemotherapy on bone
Publisher: Wiley
Date: 17-12-2013
DOI: 10.1002/JOR.22565
Abstract: Methotrexate (MTX) chemotherapy is known to cause bone loss which lacks specific preventative treatments, although clinically folinic acid is often used to reduce MTX toxicity in soft tissues. This study investigated damaging effects of MTX injections (0.75 mg/kg/day for 5 days) in rats and potential protective benefits of fish oil (0.25, 0.5, or 0.75 ml/100 g/day) in comparison to folinic acid (0.75 mg/kg) in the tibial metaphysis. MTX treatment significantly reduced height of primary spongiosa and volume of trabecular bone while reducing density of osteoblasts. Consistently, MTX reduced osteogenic differentiation but increased adipogenesis of bone marrow stromal cells, accompanied by lower mRNA expression of osteogenic transcription factors Runx2 and Osx, but an up-regulation of adipogenesis-related genes FABP4 and PPAR-γ. MTX also increased osteoclast density, bone marrow osteoclast formation, and mRNA expression of proinflammatory cytokines IL-1, IL-6, TNF-α, and RANKL/OPG ratio in bone. Fish oil (0.5 or 0.75 ml/100 g) or folinic acid supplementation preserved bone volume, osteoblast density, and osteogenic differentiation, and suppressed MTX-induced cytokine expression, osteoclastogenesis, and adipogenesis. Thus, fish oil at 0.5 ml/100 g or above is as effective as folinic acid in counteracting MTX-induced bone damage, conserving bone formation, suppressing resorption and marrow adiposity, suggesting its therapeutic potential in preventing bone loss during MTX chemotherapy.
Expression of transforming growth factor-α mRNA and peptide in rodent kidneys
Publisher: Springer Science and Business Media LLC
Date: 21-06-1999
Abstract: The expression and function of transforming growth factor alpha (TGF-(alpha) in the kidney are not fully characterised. There exists controversy concerning the detection of renal TGF-alpha mRNA and the localisation of its immunoreactivity. In attempts to clarify the detection and localisation issue, the present study aimed to detect TGF-alpha mRNA in neonate and adult rat kidneys, to examine the specificity of two commonly used anti-TGF-alpha antibodies and finally to localise renal TGF-alpha immunoreactivity using a specific antibody. TGF-alpha mRNA of around 4.8 kb was readily detected with a sensitive nonradioactive northern analysis, with a similar abundance in neonatal and adult rat kidneys. Renal TGF-alpha peptide of the 6-kDa mature form was identified by western blotting. By using various controls, including specimens from TGF-alpha knock out mice in comparison with wild-type mice, the present study has confirmed the specificity of a polyclonal anti-human recombinant TGF-alpha antibody. With this antibody, TGF-alpha immunoreactivity was localised to the proximal tubules in renal cortex. In addition, the present study has also demonstrated a non-specificity in localising TGF-alpha in rodent kidneys by the most commonly used monoclonal anti-human TGF-alpha C-terminal peptide antibody, which stained collecting ducts in renal cortex and medulla.
Regulation of bone morphogenetic protein signalling and cranial osteogenesis by Gpc1 and Gpc3.
Publisher: Elsevier BV
Date: 08-2013
DOI: 10.1016/J.BONE.2013.04.013
Abstract: From birth, the vault of the skull grows at a prodigious rate, driven by the activity of osteoblastic cells at the fibrous joints (sutures) that separate the bony calvarial plates. One in 2500 children is born with a medical condition known as craniosynostosis because of premature bony fusion of the calvarial plates and a cessation of bone growth at the sutures. Bone morphogenetic proteins (BMPs) are potent growth factors that promote bone formation. Previously, we found that Glypican-1 (GPC1) and Glypican-3 (GPC3) are expressed in cranial sutures and are decreased during premature suture fusion in children. Although glypicans are known to regulate BMP signalling, a mechanistic link between GPC1, GPC3 and BMPs and osteogenesis has not yet been investigated. We now report that human primary suture mesenchymal cells coexpress GPC1 and GPC3 on the cell surface and release them into the media. We show that they inhibit BMP2, BMP4 and BMP7 activities, which both physically interact with BMP2 and that immunoblockade of endogenous GPC1 and GPC3 potentiates BMP2 activity. In contrast, increased levels of GPC1 and GPC3 as a result of overexpression or the addition of recombinant protein, inhibit BMP2 signalling and BMP2-mediated osteogenesis. We demonstrate that BMP signalling in suture mesenchymal cells is mediated by both SMAD-dependent and SMAD-independent pathways and that GPC1 and GPC3 inhibit both pathways. GPC3 inhibition of BMP2 activity is independent of attachment of the glypican on the cell surface and post-translational glycanation, and thus appears to be mediated by the core glypican protein. The discovery that GPC1 and GPC3 regulate BMP2-mediated osteogenesis, and that inhibition of endogenous GPC1 and GPC3 potentiates BMP2 responsiveness of human suture mesenchymal cells, indicates how downregulation of glypican expression could lead to the bony suture fusion that characterizes craniosynostosis.
Endogenous BDNF is required for myelination and regeneration of injured sciatic nerve in rodents.
Publisher: Wiley
Date: 12-2000
Exploring thermal reversible hydrogels for stem cell expansion in three-dimensions
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2SM25407G
Combination chemotherapy with cyclophosphamide, epirubicin and 5-fluorouracil causes trabecular bone loss, bone marrow cell depletion and marrow adiposity in female rats
Publisher: Springer Science and Business Media LLC
Date: 09-06-2015
DOI: 10.1007/S00774-015-0679-X
Abstract: The introduction of anthracyclines to adjuvant chemotherapy has increased survival rates among breast cancer patients. Cyclophosphamide, epirubicin and 5-fluorouracil (CEF) combination therapy is now one of the preferred regimens for treating node-positive breast cancer due to better survival with less toxicity involved. Despite the increasing use of CEF, its potential in causing adverse skeletal effects remains unclear. Using a mature female rat model mimicking the clinical setting, this study examined the effects of CEF treatment on bone and bone marrow in long bones. Following six cycles of CEF treatment (weekly intravenous injections of cyclophosphamide at 10 mg/kg, epirubicin at 2.5 mg/kg and 5-flurouracil at 10 mg/kg), a significant reduction in trabecular bone volume was observed at the metaphysis, which was associated with a reduced serum level of bone formation marker alkaline phosphatase (ALP), increased trends of osteoclast density and osteoclast area at the metaphysis, as well as an increased size of osteoclasts being formed from the bone marrow cells ex vivo. Moreover, a severe reduction of bone marrow cellularity was observed following CEF treatment, which was accompanied by an increase in marrow adipose tissue volume. This increase in marrow adiposity was associated with an expansion in adipocyte size but not in marrow adipocyte density. Overall, this study indicates that six cycles of CEF chemotherapy may induce some bone loss and severe bone marrow damage. Mechanisms for CEF-induced bone/bone marrow pathologies and potential preventive strategies warrant further investigation.
ss-Catenin signaling is important for osteogenesis and hematopoiesis recovery following methotrexate chemotherapy in rats
Publisher: Wiley
Date: 20-10-2021
DOI: 10.1002/JCP.30114
Abstract: Cancer chemotherapy can significantly impair the bone formation and cause myelosuppression however, their recovery potentials and mechanisms remain unclear. This study investigated the roles of the β‐catenin signaling pathway in bone and bone marrow recovery potentials in rats treated with antimetabolite methotrexate (MTX) (five once‐daily injections, 0.75 mg/kg) with/without β‐catenin inhibitor indocyanine green (ICG)‐001 (oral, 200 mg/kg/day). ICG alone reduced trabecular bone volume and bone marrow cellularity. In MTX‐treated rats, ICG suppressed bone volume recovery on Day 11 after the first MTX injection. ICG exacerbated MTX‐induced decreases on Day 9 osteoblast numbers on bone surfaces, their formation in vitro from bone marrow stromal cells (osteogenic differentiation/mineralization), as well as expression of osteogenesis‐related markers Runx2, Osx, and OCN in bone, and it suppressed their subsequent recoveries on Day 11. On the other hand, ICG did not affect MTX‐induced increased osteoclast density and the level of the osteoclastogenic signal (RANKL/OPG expression ratio) in bone, suggesting that ICG inhibition of β‐catenin does nothing to abate the increased bone resorption induced by MTX. ICG also attenuated bone marrow cellularity recovery on Day 11, which was associated with the suppressed recovery of CD34 + or c‐Kit + hematopoietic progenitor cell contents. Thus, β‐catenin signaling is important for osteogenesis and hematopoiesis recoveries following MTX chemotherapy.
Calmodulin‐dependent signalling pathways are activated and mediate the acute inflammatory response of injured skeletal muscle
Publisher: Wiley
Date: 10-10-2019
DOI: 10.1113/JP278478
Abstract: There is a close relationship between skeletal muscle physiology and Ca 2+ /calmodulin (CaM) signalling. Despite the effects of Ca 2+ /CaM signalling on immune and inflammatory responses having been extensively explored, few studies have investigated the role of CaM pathway activation on the post‐injury muscle inflammatory response. In this study, we investigated the role of CaM‐dependent signalling in muscle inflammation in cardiotoxin induced myoinjuries in mice. The Ca 2+ /calmodulin‐dependent protein kinase II (CaMII), Ca 2+ /calmodulin‐dependent protein kinase IV (CaMKIV), and nuclear factor of activated T cells (NFAT) pathways are likely to be simultaneously activated in muscle cells and in infiltrating lymphocytes and to regulate the immune behaviours of myofibres in an inflammatory environment, and these pathways ultimately affect the outcome of muscle inflammation. Calcium/calmodulin (Ca 2+ /CaM) signalling is essential for immune and inflammatory responses in tissues. However, it is unclear if Ca 2+ /CaM signalling interferes with muscle inflammation. Here we investigated the roles of CaM‐dependent signalling in muscle inflammation in mice that had acute myoinjuries in the tibialis anterior muscle induced by intramuscular cardiotoxin (CTX) injections and received intraperitoneal injections of either the CaM inhibitor calmidazolium chloride (CCL) or CaM agonist calcium‐like peptide 1 (CALP1). Multiple inflammatory parameters, including muscle autoantigens and toll‐like receptors, mononuclear cell infiltration, cytokines and chemokines associated with peripheral muscle inflammation, were examined after the injury and treatment. CALP1 treatment enhanced intramuscular infiltration of monocytes/macrophages into the damaged tibialis anterior muscle and up‐regulated mRNA and protein levels of muscle autoantigens (Mi‐2, HARS and Ku70) and Toll‐like receptor 3 (TLR3), and mRNA levels of tumor necrosis factor α (TNF‐α), interleukin‐6 (IL‐6), Monocyte chemoattractant protein‐1 (MCP1), Monocyte chemoattractant protein‐3 (MCP3) and Macrophage inflammatory protein‐1(MIP‐1α) in damaged muscle. In contrast, CCL treatment decreased the intramuscular cell infiltration and mRNA levels of the inflammatory mediators. After CALP1 treatment, a substantial up‐regulation in Ca 2+ /calmodulin‐dependent protein kinase II (CaMKII), Ca 2+ /calmodulin‐dependent protein kinase IV (CaMKIV) and nuclear factor of activated T cells (NFAT) activity was detected in CD45 + cells isolated from the damaged muscle. More pro‐inflammatory F4/80 + Ly‐6C + cells were detected in CD45‐gated cells after CALP1 treatment than in those after CCL treatment or no treatment. Consistently, in interferon‐γ‐stimulated cultured myoblasts and myotubes, CALP1 treatment up‐regulated the activities of CaMKII, CaMKIV and NFAT, and levels of class I/II major histocompatibility complexes (MHC‐I/II) and TLR3. Our findings demonstrated that CaM‐dependent signalling pathways mediate the injury‐induced acute muscle inflammatory response.
Role of FGFs/FGFRs in skeletal development and bone regeneration
Publisher: Wiley
Date: 23-08-2012
DOI: 10.1002/JCP.24083
Abstract: Fibroblast growth factor (FGF)/FGF (FGFR) signaling is an important pathway involved in skeletal development. Missense mutations in FGFs and FGFRs were found clinically to cause multiple congenital skeleton diseases including chondrodysplasia, craniosynostosis, syndromes with dysregulated phosphate metabolism. FGFs/FGFRs also have crucial roles in bone fracture repair and bone regeneration. Understanding the molecular mechanisms for the role of FGFs/FGFRs in the regulation of skeletal development, genetic skeletal diseases, and fracture healing will ultimately lead to better treatment of skeleton diseases caused by mutations of FGFs/FGFRs and fracture. This review summarizes the major findings on the role of FGF signaling in skeletal development, genetic skeletal diseases and bone healing, and discusses issues that remain to be resolved in applying FGF signaling-related measures to promote bone healing. This review has also provided a perspective view on future work for exploring the roles and action mechanisms of FGF signaling in skeletal development, genetic skeletal diseases, and fracture healing.
Icariin attenuates methotrexate chemotherapy-induced bone marrow microvascular damage and bone loss in rats
Publisher: Wiley
Date: 19-02-2019
DOI: 10.1002/JCP.28326
Abstract: Methotrexate (MTX), a widely used antimetabolite in paediatric cancer to treatment, has been widely reported to cause bone loss and bone marrow (BM) microvascular (particularly sinusoids) damage. Investigations must now investigate how MTX‐induced bone loss and microvasculature damage can be attenuated revented. In the present study, we examined the potency of icariin, an herbal flavonoid, in reducing bone loss and the dilation/damage of BM sinusoids in rats caused by MTX treatment. Groups of young rats were treated with five daily MTX injections (0.75 mg/kg) with and without icariin oral supplementation until Day 9 after the first MTX injection. Histological analyses showed a significant reduction in the bone volume/tissue volume (BV/TV) fraction (%) and trabecular number in the metaphysis trabecular bone of MTX‐treated rats, but no significant changes in trabecular thickness and trabecular spacing. However, the BV/TV (%) and trabecular number were found to be significantly higher in MTX + icariin‐treated rats than those of MTX alone‐treated rats. Gene expression analyses showed that icariin treatment maintained expression of osteogenesis‐related genes but suppressed the induction of adipogenesis‐related genes in bones of MTX‐treated rats. In addition, icariin treatment attenuated MTX‐induced dilation of BM sinusoids and upregulated expression of endothelial cell marker CD31 in the metaphysis bone of icariin + MTX‐treated rats. Furthermore, in vitro studies suggest that icariin treatment can potentially enhance the survival of cultured rat sinusoidal endothelial cells against cytotoxic effect of MTX and promote their migration and tube formation abilities, which is associated with enhanced production of nitric oxide.
Potential roles of metallothioneins I and II in protecting bone growth following acute methotrexate chemotherapy
Publisher: Informa UK Limited
Date: 06-12-2013
A hybrid platform for three-dimensional printing of bone scaffold by combining thermal-extrusion and electrospinning methods
Publisher: Springer Science and Business Media LLC
Date: 05-02-2020
Microgravity induces inhibition of osteoblastic differentiation and mineralization through abrogating primary cilia
Publisher: Springer Science and Business Media LLC
Date: 12-05-2017
DOI: 10.1038/S41598-017-02049-9
Abstract: It is well documented that microgravity in space environment leads to bone loss in astronauts. These physiological changes have also been validated by human and animal studies and modeled in cell-based analogs. However, the underlying mechanisms are elusive. In the current study, we identified a novel phenomenon that primary cilia (key sensors and functioning organelles) of rat calvarial osteoblasts (ROBs) gradually shrank and disappeared almost completely after exposure to simulated microgravity generated by a random positioning machine (RPM). Along with the abrogation of primary cilia, the differentiation, maturation and mineralization of ROBs were inhibited. We also found that the disappearance of primary cilia was prevented by treating ROBs with cytochalasin D, but not with LiCl or dynein light chain Tctex-type 1 (Dynlt1) siRNA. The repression of the differentiation, maturation and mineralization of ROBs was effectively offset by cytochalasin D treatment in microgravity conditions. Blocking ciliogenesis using intraflagellar transport protein 88 (IFT88) siRNA knockdown inhibited the ability of cytochalasin D to counteract this reduction of osteogenesis. These results indicate that the abrogation of primary cilia may be responsible for the microgravity’s inhibition on osteogenesis. Reconstruction of primary cilia may become a potential strategy against bone loss induced by microgravity.
Preparation of adriamycin gelatin microsphere‐loaded decellularized periosteum that is cytotoxic to human osteosarcoma cells
Publisher: Wiley
Date: 27-11-2019
DOI: 10.1002/JCP.27753
Abstract: The purpose of this study was to develop a novel approach to treat bone osteosarcoma using a multipurpose scaffold aiming for local drug delivery. The slowly releasing microspheres was designed to deliver the chemotherapy drug adriamycin (ADM) and a decellularized (D) periosteum scaffold (which is known to be able to promote bone regeneration) was used to carry these microspheres. D‐periosteum was obtained by physical and chemical decellularization. Histological results showed that the cellular components were effectively removed. The D‐periosteum showed an excellent cytocompatibility and the ability to promote adhesion and growth of fibroblasts. Two kinds of slowly releasing microspheres, adriamycin gelatin microspheres (ADM‐GMS) and adriamycin poly (dl‐lactide‐co‐glycolide) gelatin microspheres (ADM‐PLGA‐GMS), were prepared and anchored to D‐periosteum, resulting in two types of drug‐releasing regenerative scaffolds. The effectiveness of these two scaffolds in killing human osteosarcoma cells was tested by evaluating cell viability overtime of the cancer cells cultured with the scaffolds. In summary, a gelatin/decellularized periosteum‐based biologic scaffold material was designed aiming for local delivery of chemotherapy drugs for osteosarcoma, with the results showing ability of the scaffolds in sustaining release of the cancer drug and in suppressing growth of the cancer cells in vitro.
Effect of reaction conditions on the lifetime of SAPO-34 catalysts in methanol to olefins process – A review
Publisher: Elsevier BV
Date: 2021
The role of osteocyte apoptosis in cancer chemotherapy-induced bone loss
Publisher: Wiley
Date: 20-03-2012
DOI: 10.1002/JCP.23034
Short-Term Hypoxia Accelerates Bone Loss in Ovariectomized Rats by Suppressing Osteoblastogenesis but Enhancing Osteoclastogenesis
Publisher: International Scientific Information, Inc.
Date: 23-08-2016
DOI: 10.12659/MSM.899485
Abstract: BACKGROUND Although it has been reported that hypoxic exposure can attenuate hypertension, heart disease, diabetes, and some other diseases, effects of hypoxia on osteoporosis are still unknown. MATERIAL AND METHODS The current study investigated whether short-term hypoxic exposure (in comparison with normoxic conditions) affects bone metabolism in normal or ovariectomized (OVX) adult female rats in an vivo study. Micro-computed tomography bone volume/structural analyses, histological examination, and serum bone turnover biochemical assays were used. In addition, the expressions of some associated major regulatory molecules were measured in osteoblastic cultures. RESULTS While the 14-day hypoxic exposure did not change the bone-remodeling process in normal adult female rats, it decreased bone volume, osteoclast density, and serum bone formation marker (alkaline phosphatase) level, but increased osteoclast density and serum bone resorption marker (C-telopeptide of collagen) level in OVX rats. The bone marrow adipocyte number and serum fatty acid binding protein-4 level were increased in OVX-hypoxic rats compared with OVX-normoxic rats. Consistently, in human MG-63 osteoblastic cultures, the hypoxic condition suppressed protein expression of osteogenic transcriptional factors Runx2 and osterix, elevated protein expression of osteoclastogenic cytokine receptor activator of nuclear factor kappa-B ligand, but reduced that of osteoclastogenic inhibitor osteoprotegerin. CONCLUSIONS Our results suggest that, although no change occurred in the bone-remodeling process in normal adult female rats after hypoxic exposure, under the estrogen-deficient osteoporotic condition, the hypoxic condition can alter the bone microenvironment so that it may further impair osteoblastic differentiation and enhance osteoclastic formation, and thus reduce bone formation, enhance bone resorption, and accelerate bone loss.
A Possible Role of Intestinal Microbiota in the Pathogenesis of Ankylosing Spondylitis
Publisher: MDPI AG
Date: 17-12-2016
DOI: 10.3390/IJMS17122126
The potential role of VEGF-induced vascularisation in the bony repair of injured growth plate
Publisher: Bioscientifica
Date: 24-01-2014
DOI: 10.1530/JOE-13-0539
Abstract: Growth plate injuries often result in undesirable bony repair causing bone growth defects, for which the underlying mechanisms are unclear. Whilst the key importance of pro-angiogenic vascular endothelial growth factor (VEGF) is well-known in bone development and fracture repair, its role during growth plate bony repair remains unexplored. Using a rat tibial growth plate injury repair model with anti-VEGF antibody, Bevacizumab, as a single i.p. injection (2.5 mg/kg) after injury, this study examined the roles of VEGF-driven angiogenesis during growth plate bony repair. Histology analyses observed isolectin-B 4 -positive endothelial cells and blood vessel-like structures within the injury site on days 6 and 14, with anti-VEGF treatment significantly decreasing blood-vessel-like structures within the injury site ( P .05). Compared with untreated controls, anti-VEGF treatment resulted in an increase in undifferentiated mesenchymal repair tissue, but decreased bony tissue at the injury site at day 14 ( P .01). Consistently, microcomputed tomography analysis of the injury site showed significantly decreased bony repair tissue after treatment ( P .01). RT-PCR analyses revealed a significant decrease in osteocalcin ( P .01) and a decreasing trend in Runx2 expression at the injury site following treatment. Furthermore, growth plate injury-induced reduced tibial lengthening was more pronounced in anti-VEGF-treated injured rats on day 60, consistent with the observation of a significantly increased height of the hypertrophic zone adjacent to the growth plate injury site ( P .05). These results indicate that VEGF is important for angiogenesis and formation of bony repair tissue at the growth plate injury site as well as for endochondral bone lengthening function of the uninjured growth plate.
Roles of EGF family of growth factors in growth: Overview of their roles in postnatal growth and development
Publisher: Springer New York
Date: 25-10-2012
Roles of neurotrophins in skeletal tissue formation and healing
Publisher: Wiley
Date: 23-05-2018
DOI: 10.1002/JCP.25936
Abstract: Neurotrophins and their receptors are key molecules that are known to be critical in regulating nervous system development and maintenance and have been recognized to be also involved in regulating tissue formation and healing in skeletal tissues. Studies have shown that neurotrophins and their receptors are widely expressed in skeletal tissues, implicated in chondrogenesis, osteoblastogenesis, and osteoclastogenesis, and are also involved in regulating tissue formation and healing events in skeletal tissue. Increased mRNA expression for neurotrophins NGF, BDNF, NT-3, and NT-4, and their Trk receptors has been observed in injured bone tissues, and NT-3 and its receptor, TrkC, have been identified to have the highest induction at the injury site in a drill-hole injury repair model in both bone and the growth plate. In addition, NT-3 has also recently been shown to be both an osteogenic and angiogenic factor, and this neurotrophin can also enhance expression of the key osteogenic factor, BMP-2, as well as the major angiogenic factor, VEGF, to promote bone formation, vascularization, and healing of the injury site. Further studies, however, are needed to investigate if different neurotrophins have differential roles in skeletal repair, and if NT-3 can be a potential target of intervention for promoting bone fracture healing.
miR-6315 attenuates methotrexate treatment-induced decreased osteogenesis and increased adipogenesis potentially through modulating TGF-ss/smad2 signalling
Publisher: MDPI AG
Date: 16-12-2021
DOI: 10.3390/BIOMEDICINES9121926
Abstract: Methotrexate (MTX) treatment for childhood malignancies has shown decreased osteogenesis and increased adipogenesis in bone marrow stromal cells (BMSCs), leading to bone loss and bone marrow adiposity, for which the molecular mechanisms are not fully understood. Currently, microRNAs (miRNAs) are emerging as vital mediators involved in bone/bone marrow fat homeostasis and our previous studies have demonstrated that miR-6315 was upregulated in bones of MTX-treated rats, which might be associated with bone/fat imbalance by directly targeting Smad2. However, the underlying mechanisms by which miR-6315 regulates osteogenic and adipogenic differentiation require more investigations. Herein, we further explored and elucidated the regulatory roles of miR-6315 in osteogenesis and adipogenesis using in vitro cell models. We found that miR-6315 promotes osteogenic differentiation and it alleviates MTX-induced increased adipogenesis. Furthermore, our results suggest that the involvement of miR-6315 in osteogenesis/adipogenesis regulation might be partially through modulating the TGF-β/Smad2 signalling pathway. Our findings indicated that miR-6315 may be important in regulating osteogenesis and adipogenesis and might be a therapeutic target for preventing/attenuating MTX treatment-associated bone loss and marrow adiposity.
Widespread differential maternal and paternal genome effects on fetal bone phenotype at mid-gestation
Publisher: Wiley
Date: 20-10-2014
DOI: 10.1002/JBMR.2263
Abstract: Parent-of-origin-dependent (epi)genetic factors are important determinants of prenatal development that program adult phenotype. However, data on magnitude and specificity of maternal and paternal genome effects on fetal bone are lacking. We used an outbred bovine model to dissect and quantify effects of parental genomes, fetal sex, and nongenetic maternal effects on the fetal skeleton and analyzed phenotypic and molecular relationships between fetal muscle and bone. Analysis of 51 bone morphometric and weight parameters from 72 fetuses recovered at day 153 gestation (54% term) identified six principal components (PC1-6) that explained 80% of the variation in skeletal parameters. Parental genomes accounted for most of the variation in bone wet weight (PC1, 72.1%), limb ossification (PC2, 99.8%), flat bone size (PC4, 99.7%), and axial skeletal growth (PC5, 96.9%). Limb length showed lesser effects of parental genomes (PC3, 40.8%) and a significant nongenetic maternal effect (gestational weight gain, 29%). Fetal sex affected bone wet weight (PC1, p < 0.0001) and limb length (PC3, p < 0.05). Partitioning of variation explained by parental genomes revealed strong maternal genome effects on bone wet weight (74.1%, p < 0.0001) and axial skeletal growth (93.5%, p < 0.001), whereas paternal genome controlled limb ossification (95.1%, p < 0.0001). Histomorphometric data revealed strong maternal genome effects on growth plate height (98.6%, p < 0.0001) and trabecular thickness (85.5%, p < 0.0001) in distal femur. Parental genome effects on fetal bone were mirrored by maternal genome effects on fetal serum 25-hydroxyvitamin D (96.9%, p < 0.001) and paternal genome effects on alkaline phosphatase (90.0%, p < 0.001) and their correlations with maternally controlled bone wet weight and paternally controlled limb ossification, respectively. Bone wet weight and flat bone size correlated positively with muscle weight (r = 0.84 and 0.77, p < 0.0001) and negatively with muscle H19 expression (r = -0.34 and -0.31, p < 0.01). Because imprinted maternally expressed H19 regulates growth factors by miRNA interference, this suggests muscle-bone interaction via epigenetic factors.
Intermittent pth (1-34) injection rescues the retarded skeletal development and postnatal lethality of mice mimicking human achondroplasia and thanatophoric dysplasia
Publisher: Oxford University Press (OUP)
Date: 24-05-2012
DOI: 10.1093/HMG/DDS181
Abstract: Achondroplasia (ACH) and thanatophoric dysplasia (TD) are caused by gain-of-function mutations of fibroblast growth factor receptor 3 (FGFR3) and they are the most common forms of dwarfism and lethal dwarfism, respectively. Currently, there are few effective treatments for ACH. For the neonatal lethality of TD patients, no practical effective therapies are available. We here showed that systemic intermittent PTH (1-34) injection can rescue the lethal phenotype of TD type II (TDII) mice and significantly alleviate the retarded skeleton development of ACH mice. PTH-treated ACH mice had longer naso-anal length than ACH control mice, and the bone lengths of humeri and tibiae were rescued to be comparable with those of wild-type control mice. Our study also found that the premature fusion of cranial synchondroses in ACH mice was partially corrected after the PTH (1-34) treatment, suggesting that the PTH treatment may rescue the progressive narrowing of neurocentral synchondroses that cannot be readily corrected by surgery. In addition, we found that the PTH treatment can improve the osteopenia and bone structure of ACH mice. The increased expression of PTHrP and down-regulated FGFR3 level may be responsible for the positive effects of PTH on bone phenotype of ACH and TDII mice.
Bmi deficiency causes oxidative stress and intervertebral disc degeneration which can be alleviated by antioxidant treatment
Publisher: Wiley
Date: 24-06-2020
DOI: 10.1111/JCMM.15528
Interaction of dietary zinc and intracellular binding protein metallothionein in postnatal bone growth
Publisher: Elsevier BV
Date: 06-2009
DOI: 10.1016/J.BONE.2009.02.011
Abstract: Zinc and its binding protein, metallothionein (MT), are important in regulating growth and development, and yet it is unclear how dietary Zn and MT interact in regulating bone growth. Here, 3.5-week female MT-I&II knockout (MT(-/-)) and wild type (MT(+/+)) mice were fed diets containing 2.5 (limiting, Zn-L), 15 or 50 mg Zn/kg (Zn adequate) for 5 or 9 weeks, and effects were analysed on structure and function of growth plate and metaphysis, two structures important for bone growth. Zn limitation did not affect bone growth in MT(+/+) mice. However, MT(-/-) mice, having lower Zn concentrations in plasma and long bone, showed growth retardation as demonstrated by lower body length gain, shorter and smaller tibia/femur, lower chondrocyte proliferation, reduced metaphysis heights, but increased osteoclast densities on trabecular bone, particularly in mice fed Zn-L diet. Interestingly, mRNA expression of MT-I&II was induced in the growth plate of MT(+/+) mice fed the Zn-L diet possibly compensating for Zn limitation. Growth plate MT-III expression increased in MT(-/-) mice fed the adequate Zn diet, whereas metaphyseal MT-III was significantly upregulated in MT(-/-) mice fed Zn-L diet, possibly as a compensatory mechanism or exacerbating effects of Zn limitation. Consistent with the increased osteoclast numbers, a higher ratio of RANKL/OPG gene expression was found in bone of mutant mice fed lower Zn diets. These results indicate that interaction between dietary Zn and endogenous MT is important for maximal bone growth, and MT is particularly important in the regulation of Zn pool for bone growth during moderate Zn limitation.
Effects of acute 5-fluorouracil chemotherapy and insulin-like growth factor-I pretreatment on growth plate cartilage and metaphyseal bone in rats
Publisher: Elsevier BV
Date: 09-2004
Treating skeletal pain: Limitations of conventional anti-inflammatory drugs, and anti-neurotrophic factor as a possible alternative
Publisher: Springer Science and Business Media LLC
Date: 02-2009
DOI: 10.1038/NCPRHEUM0982
Abstract: Inflammatory and injury-induced skeletal pain are common conditions, and both conventional nonselective NSAIDs and the newer cyclo-oxygenase-2-specific inhibitors are widely used as post-traumatic and post-surgical analgesics. However, new research suggests that these drugs, particularly the cyclo-oxygenase-2 inhibitors, have a negative effect on the healing process in fractured bone and within orthopedic surgical sites, thus highlighting a need to develop new approaches for managing skeletal pain. Various experimental studies have revealed that locally upregulated neurotrophic factors, especially nerve growth factor, have a major role in mediating injury-induced or inflammatory pain. Nerve growth factor inhibitors, therefore, might be an effective alternative modality for post-traumatic and post-surgical analgesia, without impairing bone healing.
The prenyl group contributes to activities of phytoestrogen 8-prenynaringenin in enhancing bone formation and inhibiting bone resorption in vitro.
Publisher: The Endocrine Society
Date: 03-2013
DOI: 10.1210/EN.2012-2086
Abstract: Previous studies have found that 8-prenylflavonoids have a higher osteogenic activity than do flavonoids, which suggested that the 8-prenyl group may play an active role in bone-protective properties. To address this hypothesis, activities of 8-prenylnaringenin (PNG) and naringenin (NG) in osteoblast and osteoclast differentiation and function were compared in vitro. PNG was found to have a stronger ability than NG to improve osteoblast differentiation and osteogenic function in cultured rat calvarial osteoblasts, as demonstrated by levels of alkaline phosphatase activity, osteocalcin, calcium deposition, and the number and area of mineralized bone nodules, as well as mRNA expression of osteogenesis-related genes Bmp-2, OSX, and Runx-2. In addition, although expression of osteoclastogenic inducer receptor activator of nuclear factor kappa-B ligand (RANKL) was not affected, that of osteoclastogenesis inhibitor osteoprotegerin (OPG) and consequently the OPG/RANKL ratio were increased, more potently by PNG than NG. PNG was also found to have a higher potency than NG in inhibiting the osteoclast formation in rabbit bone marrow cells and their resorptive activity, as revealed by lower numbers of osteoclasts formed, lower numbers and areas of bone resorption pits, and lower mRNA expression levels of tartrate-resistant acid phosphatase and cathepsin K. Furthermore, PNG induced apoptosis of mature osteoclasts at a higher degree and at an earlier time than did NG. These results indicate that the 8-prenyl group plays an important role and contributes to the higher bone-protective activity of PNG in comparison with NG.
Neurotrophin-3 induces BMP-2 and VEGF activities and promotes the bony repair of injured growth plate cartilage and bone in rats
Publisher: Wiley
Date: 25-02-0002
DOI: 10.1002/JBMR.2786
Abstract: Injured growth plate is often repaired by bony tissue causing bone growth defects, for which the mechanisms remain unclear. Because neurotrophins have been implicated in bone fracture repair, here we investigated their potential roles in growth plate bony repair in rats. After a drill-hole injury was made in the tibial growth plate and bone, increased injury site mRNA expression was observed for neurotrophins NGF, BDNF, NT-3, and NT-4 and their Trk receptors. NT-3 and its receptor TrkC showed the highest induction. NT-3 was localized to repairing cells, whereas TrkC was observed in stromal cells, osteoblasts, and blood vessel cells at the injury site. Moreover, systemic NT-3 immunoneutralization reduced bone volume at injury sites and also reduced vascularization at the injured growth plate, whereas recombinant NT-3 treatment promoted bony repair with elevated levels of mRNA for osteogenic markers and bone morphogenetic protein (BMP-2) and increased vascularization and mRNA for vascular endothelial growth factor (VEGF) and endothelial cell marker CD31 at the injured growth plate. When examined in vitro, NT-3 promoted osteogenesis in rat bone marrow stromal cells, induced Erk1/2 and Akt phosphorylation, and enhanced expression of BMPs (particularly BMP-2) and VEGF in the mineralizing cells. It also induced CD31 and VEGF mRNA in rat primary endothelial cell culture. BMP activity appears critical for NT-3 osteogenic effect in vitro because it can be almost completely abrogated by co-addition of the BMP inhibitor noggin. Consistent with its angiogenic effect in vivo, NT-3 promoted angiogenesis in metatarsal bone explants, an effect abolished by co-treatment with anti-VEGF. This study suggests that NT-3 may be an osteogenic and angiogenic factor upstream of BMP-2 and VEGF in bony repair, and further studies are required to investigate whether NT-3 may be a potential target for preventing growth plate faulty bony repair or for promoting bone fracture healing. © 2016 American Society for Bone and Mineral Research.
Clinicopathological significance of glucose transporter protein-1 overexpression in human osteosarcoma
Publisher: Spandidos Publications
Date: 21-06-2017
DOI: 10.3892/OL.2017.6437
Long chain omega-3 polyunsaturated fatty acid supplementation protects against adriamycin and cyclophosphamide chemotherapy-induced bone marrow damage in female rats
Publisher: MDPI AG
Date: 06-02-2018
DOI: 10.3390/IJMS19020484
Combination breast cancer chemotherapy with doxorubicin and cyclophosphamide damages bone and bone marrow in a female rat model
Publisher: Springer Science and Business Media LLC
Date: 26-05-2017
DOI: 10.1007/S10549-017-4308-3
Abstract: Anthracyclines (including doxorubicin) are still the backbone of commonly used breast cancer chemotherapy regimens. Despite increasing use of doxorubicin and cyclophosphamide (AC) combinations for treating breast cancer, their potential to cause adverse skeletal effects remains unclear. This study examined the effects of treatments with the AC regimen on bone and bone marrow in adult female rats. AC treatment for four cycles (weekly intravenous injection of 2 mg/kg doxorubicin and 20 mg/kg cyclophosphamide) resulted in a reduced volume of trabecular bone at the metaphysis, which was associated with reduced serum levels of 25-hydroxy vitamin D3 and alkaline phosphatase. Reductions in densities of osteocytes and bone lining cells were also observed. In addition, bone marrow was severely damaged, including a severe reduction in bone marrow cellularity and an increase in marrow adipocyte content. Accompanying these changes, there were increases in mRNA expression of adipogenesis regulatory genes (PPARγ and FABP4) and an inflammatory cytokine (TNFα) in metaphysis bone and bone marrow. This study indicates that AC chemotherapy may induce some bone loss, due to reduced bone formation, and bone marrow damage, due to increased marrow adiposity. Preventive strategies for preserving the bone and bone marrow microenvironment during anthracycline chemotherapy warrant further investigation.
Roles of Wnt signalling in bone growth, remodelling, skeletal disorders and fracture repair
Publisher: Wiley
Date: 2008
DOI: 10.1002/JCP.21342
Abstract: Wnt signalling has an essential role in regulating bone formation and remodelling during embryonic development and throughout postnatal and adult life. Specifically, Wnt signalling regulates bone formation by controlling embryonic cartilage development and postnatal chondrogenesis, osteoblastogenesis, osteoclastogenesis, endochondral bone formation, and bone remodelling. Abnormalities in the function of Wnt genes give rise to or contribute to the development of several pathological bone conditions, including abnormal bone mass, osteosarcomas and bone loss in multiple myeloma. Furthermore, Wnt signalling is activated during bone fracture repair and plays a crucial role in regulating bone regeneration.
Erratum: Effect of lumbar 5 ventral root transection on pain behaviors: A novel rat model for neuropathic pain without axotomy of primary sensory neurons (Experimental Neurology (2000) 175:1 (23-34) S0014488602978970)
Publisher: Elsevier BV
Date: 08-2002
Damage and recovery of the bone growth mechanism in young rats following 5-fluorouracil acute chemotherapy
Publisher: Wiley
Date: 2006
DOI: 10.1002/JCB.20889
Abstract: Chemotherapy-induced bone growth arrest and osteoporosis are significant problems in paediatric cancer patients, and yet how chemotherapy affects bone growth remains unclear. This study characterised development and resolution of damage caused by acute chemotherapy with antimetabolite 5-fluorouracil (5-FU) in young rats in the growth plate cartilage and metaphyseal bone, two important tissues responsible for bone lengthening. In metaphysis, 5-FU induced apoptosis among osteoblasts and preosteoblasts on days 1-2. In growth plate, chondrocyte apoptosis appeared on days 5-10. Interestingly, Bax was induced prior to apoptosis and Bcl-2 was upregulated during recovery. 5-FU also suppressed cell proliferation on days 1-2. While proliferation returned to normal by day 3 in metaphysis, it recovered partially on day 3, overshot on days 5-7 and normalised by day 10 in growth plate. Histologically, growth plate heights decreased by days 4-5 and returned normal by day 10. In metaphysis, primary spongiosa height was also reduced, mirroring changes in growth plate thickness. In metaphyseal secondary spongiosa, a reduced bone volume was observed on days 7-10 as there were fewer but more separated trabeculae. Starting from day 4, expression of some cartilage/bone matrix proteins and growth factors (TGF-beta1 and IGF-I) was increased. By day 14, cellular activity, histological structure and gene expression had returned normal in both tissues. Therefore, 5-FU chemotherapy affects bone growth directly by inducing apoptosis and inhibiting proliferation at growth plate cartilage and metaphyseal bone after the acute damage, bone growth mechanism can recover, which is associated with upregulated expression of matrix proteins and growth factors.
Damage and Recovery of the Bone Marrow Microenvironment Induced by Cancer Chemotherapy - Potential Regulatory Role of Chemokine CXCL12/Receptor CXCR4 Signalling
Publisher: Bentham Science Publishers Ltd.
Date: 07-2010
DOI: 10.2174/156652410791608243
Abstract: The bone marrow microenvironment houses haematopoietic stem cells (HSC), mesenchymal stem cells (MSC) and their progeny, supports haematopoiesis, osteogenesis, osteoclastogenesis, and adipogenesis. It plays a key role in maintaining homeostatic production of erythroid, myeloid or lymphoid cells, appropriate bone mass and bone health throughout life. Through cell-cell adhesion and chemotactic axes, a reciprocal inter-dependent relationship exists between these two cell lineages. Following chemotherapy-induced myelosuppression observed in cancer patients, HSCs are induced to enter into the cell cycle in order to re-establish the damaged microenvironment. These cells not only have the capacity to mobilize to the peripheral blood, but the ability to repopulate the marrow cavity as required. However, depending on the dosage and length of chemotherapy treatment, complications in bone and bone marrow recovery occur. This may manifest as marrow haematopoietic depletion, high marrow fat content, reduced bone formation and aggravated osteoclastic bone resorption. Although the molecular and cellular mechanisms governing injured states of the marrow microenvironment are yet to be fully elucidated, many reports have demonstrated the CXCL12/CXCR4 axis plays an important role in regulating the two cell lineages. Their interaction maintains bone marrow homeostasis and orchestrates its regeneration following chemotherapy. This review explores movement of MSC and HSC, haematopoiesis, commitment of osteoblasts, osteoclasts, and adipocytes, as well as the major signalling pathways that regulate these cellular processes under chemotherapy-treated conditions. This review also discusses molecular targets that are being used clinically or are currently under investigation for preserving the bone marrow microenvironment during or enhancing recovery after chemotherapy.
Dietary zinc and metallothionein on small intestinal disaccharidases activity in mice
Publisher: Baishideng Publishing Group Inc.
Date: 2011
Increased expression of HGF and c-met in rat small intestine during recovery from methotrexate-induced mucositis.
Publisher: Springer Science and Business Media LLC
Date: 02-2000
Individual or combination treatments with lapatinib and paclitaxel cause potential bone loss and bone marrow adiposity in rats
Publisher: Wiley
Date: 27-09-2019
DOI: 10.1002/JCB.27705
Abstract: Cancer treatments with cytotoxic drugs have been shown to cause bone loss. However, effects on bone are less clear for ErbB‐targeting tyrosine kinase inhibitors or their combination use with cytotoxic drugs. This study examined the effects of in idual or combination treatments with breast cancer drugs lapatinib (a dual ErbB1/ErbB2 inhibitor) and paclitaxel (a microtubule‐stabilizing cytotoxic agent) on bone and bone marrow of rats. Wistar rats received lapatinib (240 mg/kg) daily, paclitaxel (12 mg/kg) weekly, or their combination for 4 weeks, and effects on bone/bone marrow were examined at the end of week 4. Microcomputed tomographical structural analyses showed a reduction in trabecular bone volume in tibia following the lapatinib, paclitaxel or their combination treatments ( P 0.05). Histomorphometry analyses revealed marked increases in bone marrow adipocyte contents in all treatment groups. Reverse transcription polymerase chain reaction gene expression studies with bone s les and cell culture studies with isolated bone marrow stromal cells showed that the all treatment groups displayed significantly reduced levels of osterix expression and osteogenic differentiation potential but increased expression levels of adipogenesis transcription factor peroxisome proliferator‐activated receptor γ. In addition, these treatments suppressed the expression of Wnt10b and/or increased expression of Wnt antagonists (secreted frizzled‐related protein 1, Dickkopf‐related protein 1 and/or sclerostin). Furthermore, all treatment groups showed increased numbers of bone‐resorbing osteoclasts on trabecular bone surfaces, although only the lapatinib group displayed increased levels of osteoclastogenic signal (receptor activator of nuclear factor κΒ ligand/osteoclastogenesis inhibitor osteoprotegrin expression ratio) in the bones. Thus, inhibiting ErbB1 and ErbB2 by lapatinib or blocking cell ision by paclitaxel or their combination causes significant trabecular bone loss and bone marrow adiposity involving a switch in osteogenesis/adipogenesis potential, altered expression of some major molecules of the Wnt/β‐catenin signalling pathway, and increased recruitment of bone‐resorbing osteoclasts.
Dietary emu oil supplementation suppresses 5-fluorouracil chemotherapy-induced inflammation, osteoclast formation, and bone loss
Publisher: American Physiological Society
Date: 06-2012
DOI: 10.1152/AJPENDO.00587.2011
Abstract: Cancer chemotherapy can cause osteopenia or osteoporosis, and yet the underlying mechanisms remain unclear, and currently, no preventative treatments are available. This study investigated damaging effects of 5-fluorouracil (5-FU) on histological, cellular, and molecular changes in the tibial metaphysis and potential protective benefits of emu oil (EO), which is known to possess a potent anti-inflammatory property. Female dark agouti rats were gavaged orally with EO or water (1 ml·day −1 ·rat −1 ) for 1 wk before a single ip injection of 5-FU (150 mg/kg) or saline (Sal) was given. The treatment groups were H 2 O + Sal, H 2 O + 5-FU, EO + 5-FU, and EO + Sal. Oral gavage was given throughout the whole period up to 1 day before euthanasia ( days 3, 4, and 5 post-5-FU). Histological analysis showed that H 2 O + 5-FU significantly reduced heights of primary spongiosa on days 3 and 5 and trabecular bone volume of secondary spongiosa on days 3 and 4. It reduced density of osteoblasts slightly and caused an increase in the density of osteoclasts on trabecular bone surface on day 4. EO supplementation prevented reduction of osteoblasts and induction of osteoclasts and bone loss caused by 5-FU. Gene expression studies confirmed an inhibitory effect of EO on osteoclasts since it suppressed 5-FU-induced expression of proinflammatory and osteoclastogenic cytokine TNFα, osteoclast marker receptor activator of nuclear factor-κB, and osteoclast-associated receptor. Therefore, this study demonstrated that EO can counter 5-FU chemotherapy-induced inflammation in bone, preserve osteoblasts, suppress osteoclast formation, and potentially be useful in preventing 5-FU chemotherapy-induced bone loss.
Effects of Resveratrol Supplementation on Methotrexate Chemotherapy‐Induced Bone Loss
Publisher: MDPI AG
Date: 09-03-2017
DOI: 10.3390/NU9030255
Preclinical studies on growth plate cartilage regeneration using chondrocytes or mesenchymal stem cells
Publisher: Humana Press
Date: 2013
Damaging effects of chronic low-dose methotrexate usage on primary bone formation in young rats and potential protective effects of folinic acid supplementary treatment
Publisher: Elsevier BV
Date: 2009
DOI: 10.1016/J.BONE.2008.09.014
Abstract: Methotrexate (MTX) is a most commonly used anti-metabolite in cancer treatment and as an anti-rheumatic drug. While MTX chemotherapy at a high dose is known to cause bone growth defects in growing bones, effects of its chronic use at a low dose on growing skeleton remain less clear. Here, we examined effects on bone growth of long-term MTX chemotherapy at a low dose in young rats, and potential protective effects of supplementary treatment with antidote folinic acid (given ip at 1 mg/kg 6 h after MTX). After two cycles of 5 once-daily MTX injections (at 0.75 mg/kg, 5 days on/9 days off/5 days on), histological analysis showed that MTX at this dose caused significant reduction in heights of growth plate and primary spongiosa bone on day 22 compared to controls (P<0.05). In contrast, a similar dosing regimen but at a lower dose (0.4 mg/kg) caused only slight or no reduction in heights of both regions. However, after the induction phase at this 0.4 mg/kg dosing, continued use of MTX at a low dose (once weekly at 0.2 mg/kg) caused a reduction in primary spongiosa height and bone volume on weeks 9 and 14, which was associated with an increased osteoclast formation and their bone surface density as well as a decreased osteoblast bone surface density in the primary spongiosa. Folinic acid supplementation was shown able to prevent the MTX effects in the primary spongiosa. These results suggest that acute use of MTX can damage growth plate and primary bone at a high dose, but not at a low dose. However, long-term use of MTX at a low dose can reduce primary bone formation probably due to decreased osteoblastic function but increased osteoclastic formation and function, and supplementary treatment with folinic acid may be potentially useful in protecting bone growth during long-term low-dose MTX chemotherapy.
Effects of Resveratrol Supplementation on Bone Growth in Young Rats and Microarchitecture and Remodeling in Ageing Rats
Publisher: MDPI AG
Date: 16-12-2014
DOI: 10.3390/NU6125871
Roles of micrornas in osteogenesis or adipogenesis differentiation of bone marrow stromal progenitor cells
Publisher: MDPI AG
Date: 05-07-2021
DOI: 10.3390/IJMS22137210
Abstract: Bone marrow stromal cells (BMSCs) are multipotent cells which can differentiate into chondrocytes, osteoblasts, and fat cells. Under pathological stress, reduced bone formation in favour of fat formation in the bone marrow has been observed through a switch in the differentiation of BMSCs. The bone/fat switch causes bone growth defects and disordered bone metabolism in bone marrow, for which the mechanisms remain unclear, and treatments are lacking. Studies suggest that small non-coding RNAs (microRNAs) could participate in regulating BMSC differentiation by disrupting the post-transcription of target genes, leading to bone/fat formation changes. This review presents an emerging concept of microRNA regulation in the bone/fat formation switch in bone marrow, the evidence for which is assembled mainly from in vivo and in vitro human or animal models. Characterization of changes to microRNAs reveals novel networks that mediate signalling and factors in regulating bone/fat switch and homeostasis. Recent advances in our understanding of microRNAs in their control in BMSC differentiation have provided valuable insights into underlying mechanisms and may have significant potential in development of new therapeutics.
CFD Analysis on the Diffusion and Accumulation Characteristics of Microleakage LPG in an Integrated Stove
Publisher: American Chemical Society (ACS)
Date: 28-12-2022
Steamed root of Rehmannia glutinosa Libosch (Plantaginaceae) alleviates methotrexate-induced intestinal mucositis in rats
Publisher: Elsevier BV
Date: 05-2016
DOI: 10.1016/J.JEP.2016.02.035
Abstract: Intestinal mucositis induced by chemotherapy is a severe clinical problem in cancer patients that currently lack effective interventions. In traditional Chinese medicine, chemotherapeutic toxicity is diagnosed as Qi and Yin deficiency, and steamed rehmannia root (SRR) is frequently prescribed to these patients. Whether SRR can prevent the adverse effects remains to be confirmed experimentally. The present study used a rat model to investigate potential efficacy and action mechanisms of SRR in attenuating the adverse effects caused by chemotherapy. Intraperitoneal injection of a single dose of anti-metabolite methotrexate (MTX, 25mg/kg) was given to adult Wistar rats, which also received oral gavage of water or SRR (1.08g/kg twice daily 3 days before and 4 days after MTX treatment), or calcium folinate (CF, a clinically used MTX antidote as a comparison, at 1mg/kg twice daily 36h after MTX treatment), or SRR and CF in combination. Animals were sacrificed 4 days after MTX treatment. Complete blood cell counting was carried out. Jejunum was analyzed histologically for mucosal damage, immunohistochemically for proliferating cell nuclear antigen (PCNA), and biochemically for thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH), as well as for tumor necrosis factor alpha (TNF-α). MTX treatment led to weight loss, leucopenia, polycythemia, increase in large thrombocyte ratio, intestinal villus atrophy, crypt loss and reduction in PCNA positive crypt cells, increases in mucosal TBARS and TNF-α and decrease in GSH. All these alterations were inhibited by SRR administration except leucopenia, and the effects of CF or CF plus SRR supplementation were found to be inferior to those of SRR. SRR can alleviate MTX-induced gut mucositis, which may be achieved by inhibiting MTX-induced oxidative stress and inflammatory response. These findings support the application of SRR in chemotherapy but not the combined application of SRR and CF.
Differentially expressed miRNAs in bone after methotrexate treatment
Publisher: Wiley
Date: 12-09-2022
DOI: 10.1002/JCP.30583
Abstract: Previous studies have shown that administration of antimetabolite methotrexate (MTX) caused a reduced trabecular bone volume and increased marrow adiposity (bone/fat switch), for which the underlying molecular mechanisms and recovery potential are unclear. Altered expression of microRNAs (miRNAs) has been shown to be associated with dysregulation of osteogenic and/or adipogenic differentiation by disrupting target gene expression. First, the current study confirmed the bone/fat switch following MTX treatment in precursor cell culture models in vitro. Then, using a rat intensive 5‐once daily MTX treatment model, this study aimed to identify miRNAs associated with bone damage and recovery (in a time course over Days 3, 6, 9, and 14 after the first MTX treatment). RNA isolated from bone s les of treated and control rats were subjected to miRNA array and reverse transcription‐polymerase chain reaction validation, which identified five upregulated miRNA candidates, namely, miR‐155‐5p, miR‐154‐5p, miR‐344g, miR‐6215, and miR‐6315. Target genes of these miRNAs were predicted using TargetScan and miRDB. Then, the protein‐protein network was established via STRING database, after which the miRNA‐key messenger RNA (mRNA) network was constructed by Cytoscape. Functional annotation and pathway enrichment analyses for miR‐6315 were performed by DAVID database. We found that TGF‐β signaling was the most significantly enriched pathway and subsequent dual‐luciferase assays suggested that Smad2 was the direct target of miR‐6315. Our current study showed that miR‐6315 might be a vital regulator involved in bone and marrow fat formation. Also, this study constructed a comprehensive miRNA–mRNA regulatory network, which may contribute to the pathogenesis rognosis of MTX‐associated bone loss and bone marrow adiposity.
Roles of neutrophil-mediated inflammatory response in the bony repair of injured growth plate cartilage in young rats
Publisher: Oxford University Press (OUP)
Date: 07-09-2006
DOI: 10.1189/JLB.0606365
Abstract: Injured growth plate cartilage is often repaired by bony tissue, resulting in impaired bone growth in children. Previously, injury-induced, initial inflammatory response was shown to be an acute inflammatory event containing predominantly neutrophils. To examine potential roles of neutrophils in the bony repair, a neutrophil-neutralizing antiserum or control normal serum was administered systemically in rats with growth plate injury. The inflammatory response was found temporally associated with increased expression of neutrophil chemotactic chemokine cytokine-induced neutrophil chemoattractant-1 and cytokines TNF-α and IL-1β. Following the inflammatory response, mesenchymal infiltration, chondrogenic and osteogenic responses, and bony repair were observed at the injury site. Neutrophil reduction did not significantly affect infiltration of other inflammatory cells and expression of TNF-α and IL-1β and growth factors, platelet-derived growth factor-B and TGF-β1, at the injured growth plate on Day 1 and had no effects on mesenchymal infiltration on Day 4. By Day 10, however, there was a significant reduction in proportion of mesenchymal repair tissue but an increase (although statistically insignificant) in bony trabeculae and a decrease in cartilaginous tissue within the injury site. Consistently, in antiserum-treated rats, there was an increase in expression of osteoblastic differentiation transcription factor cbf-α1 and bone matrix protein osteocalcin and a decrease in chondrogenic transcription factor Sox-9 and cartilage matrix collagen-II in the injured growth plate. These results suggest that injury-induced, neutrophil-mediated inflammatory response appears to suppress mesenchymal cell osteoblastic differentiation but enhance chondrogenic differentiation, and thus, it may be involved in regulating downstream chondrogenic and osteogenic events for growth plate bony repair.
Critical limb ischemia: Current and novel therapeutic strategies
Publisher: Wiley
Date: 13-01-2019
DOI: 10.1002/JCP.28141
Abstract: Critical limb ischemia (CLI) is the advanced stage of peripheral artery disease spectrum and is defined by limb pain or impending limb loss because of compromised blood flow to the affected extremity. Current conventional therapies for CLI include utation, bypass surgery, endovascular therapy, and pharmacological approaches. Although these conventional therapeutic strategies still remain as the mainstay of treatments for CLI, novel and promising therapeutic approaches such as proangiogenic gene rotein therapies and stem cell‐based therapies have emerged to overcome, at least partially, the limitations and disadvantages of current conventional therapeutic approaches. Such novel CLI treatment options may become even more effective when other complementary approaches such as utilizing proper bioscaffolds are used to increase the survival and engraftment of delivered genes and stem cells. Therefore, herein, we address the benefits and disadvantages of current therapeutic strategies for CLI treatment and summarize the novel and promising therapeutic approaches for CLI treatment. Our analyses also suggest that these novel CLI therapeutic strategies show considerable advantages to be used when current conventional methods have failed for CLI treatment.
Expression of proinflammatory cytokines and growth factors at the injured growth plate cartilage in young rats
Publisher: Elsevier BV
Date: 12-2004
DOI: 10.1016/J.BONE.2004.09.014
Abstract: Growth plate, a cartilage-like tissue responsible for bone lengthening in children, has limited abilities to regenerate. After injury, a bony repair often occurs at the injury site, which may lead to growth arrest or angulation of the involved long bone. Our previous study has demonstrated inflammatory, fibrogenic, and osteogenic responses at the injured growth plate however, the underlying mechanisms remain unclear. In this study, mRNA expression patterns of pro-inflammatory cytokines, growth factors, transcription factors, and matrix proteins were examined by quantitative RT-PCR over a 35-day time period after a drill-hole injury at the proximal tibial growth plate of young rats. During the initial inflammatory phase, IL-1beta expression peaked at 8-16 h, and TNF-alpha and TGF-beta1 levels peaked on day 1. During the subsequent fibrogenic response, expression of growth factors FGF-2 and PDGF-B was up-regulated on day 3 whereas levels of collagen-2a and transcription factor Sox9 remained unchanged. In the osteogenic and bone remodeling stages, levels of TNF-alpha, FGF-2, and TGF-beta1 rose again during days 25-35, and IGF-I and bone matrix protein osteocalcin elevated from days 7 to 35. The positive changes in expression of IL-1beta, TNF-alpha, TGF-beta1, and IGF-I suggest their possible roles in the early acute inflammatory event and later in the formation and remodeling of the bone bridge. The up-regulation of FGF-2 and PDGF-B, coinciding with mesenchymal cell infiltration, suggests their possible involvement in the intermediate fibrogenic response. The lack of up-regulation of Col-2a and Sox9 refutes the involvement of endochondral ossification but confirms a direct bone formation response during bone bridge formation at the injured growth plate.
Structural and molecular analyses of bone bridge formation within the growth plate injury site and cartilage degeneration at the adjacent uninjured area
Publisher: Elsevier BV
Date: 10-2011
DOI: 10.1016/J.BONE.2011.07.024
Abstract: Injury to the growth plate is common and yet the injured cartilage is often repaired with undesirable bony tissue, leading to bone growth defects in children. Using a rat tibial growth plate injury model, our previous studies have shown sequential inflammatory, fibrogenic, osteogenic and bone maturation responses involved in the bony repair. However, it remains unclear whether there is progressive accumulation of bone within the injury site and any potential degenerative changes at the adjacent non-injured area of the growth plate. This study examined effects of growth plate injury on the structure, composition and some cellular and molecular changes at the injury site and adjacent uninjured area. Micro-CT analysis revealed that while the bone volume within the injury site at day 14 was small, the bone bridge was considerably larger at the injury site by 60 days post-injury. Interestingly, formation of bone bridges in the adjacent uninjured area was detected in 60% of injured animals at day 60. Immunohistochemical analyses revealed reduced chondrocyte proliferation (PCNA labelling) but increased apoptosis (nick translation labelling) in the adjacent uninjured area. RT-PCR analysis on adjacent uninjured growth plate tissue found increased expression of osteocalcin at day 60, differential expression of apoptosis-regulatory genes and alterations in genes associated with chondrocyte proliferation/differentiation, including Sox9 and IGF-I. Therefore, this study has demonstrated progressive changes in the structure/composition of the injury site and adjacent uninjured area and identified cellular and molecular alterations or degeneration in adjacent uninjured growth plate in response to injury.
Delayed development of ossification centers in the tibia of prenatal and early postnatal MPS VII mice
Publisher: Elsevier BV
Date: 06-2018
DOI: 10.1016/J.YMGME.2018.04.014
Abstract: Short stature is a characteristic feature of most of the mucopolysaccharidoses, a group of inherited lysosomal storage disorders caused by a single enzyme deficiency. MPS patients present with progressive skeletal defects from an early age, including short stature due to impaired cartilage-to-bone conversion (endochondral ossification). The aim of this study was to determine which murine MPS model best reproduces the bone length reduction phenotype of human MPS and use this model to determine the earliest developmental stage when disrupted endochondral ossification first appears. Gus
Aberrant expression of long noncoding RNA SNHG15 correlates with liver metastasis and poor survival in colorectal cancer
Publisher: Wiley
Date: 14-10-2018
DOI: 10.1002/JCP.27456
Abstract: Long noncoding RNAs (lncRNAs) play a critical role in the initiation and progression of colorectal cancer (CRC), but little is known about the function of lncRNAs in the colorectal liver metastasis (CLM). This study was designed to identify specific lncRNAs correlating to liver metastasis of CRC, and to further assess their clinical value. Seventeen patients with primary CRC lesions, adjacent normal mucosa, and synchronous liver metastases lesions were ided into discovery set (six patients) and test set (11 patients). Transcriptome sequencing (RNAseq) was used to screen differential expression of lncRNAs in the discovery set. Based on bioinformatics data, quantitative reverse‐transcription polymerase chain reaction (qRT‐PCR) was used to verify the target lncRNA in test set. The relationships between target lncRNA and clinical values were analysed in an expanded validation set of additional 91 patients. 23 upregulated and 14 downregulated lncRNAs were detected for distinguishing synchronous liver metastases, primary CRC lesions from adjacent normal mucosa in the RNAseq set. The expression levels of four lncRNAs in the 37 lncRNA signature were verified by qRT‐PCR in the test set. Compared with the paired normal mucosa, high expression levels of lnc‐small‐nucleolar RNA host gene 15 (SNHG15) were detected not only in primary CRC lesions but also in liver metastases lesions in the test set. Furthermore, in the expanded validation set, high expression of lnc‐SNHG15 was significantly associated with lymph‐node metastasis and liver metastasis ( p 0.05), and patients displaying high lncRNA‐SNHG15 expression exhibited a shorter median overall survival duration than those displaying low expression (30.7 vs. 35.2 months p = 0.003). Multivariate analyses demonstrated that lncRNA‐SNHG15 overexpression may serve as a poor prognostic biomarker for CRC patients ( p = 0.049 Cox's regression: 2.731). Lnc‐SNHG15 overexpression was significantly associated with CLM and high‐expression of lnc‐SNHG15 in CRC was an independent predictor of poor survival.
Childhood cancer chemotherapy-induced bone damage: pathobiology and protective effects of resveratrol and other nutraceuticals
Publisher: Wiley
Date: 29-06-2017
DOI: 10.1111/NYAS.13380
Abstract: Intensive cancer chemotherapy causes significant bone loss, for which the mechanisms remain unclear and effective treatments are lacking. This is a significant issue particularly for childhood cancers, as the most common ones have a >75% cure rate following chemotherapy there is an increasing population of survivors who live with chronic bone defects. Studies suggest that these defects are the result of reduced bone from increased marrow fat formation and increased bone resorption following chemotherapy. These changes probably result from altered expression/activation of regulatory molecules or pathways regulating skeletal cell formation and activity. Treatment with methotrexate, an antimetabolite commonly used in childhood oncology, has been shown to increase levels of proinflammatory ro-osteoclastogenic cytokines (e.g., enhanced NF-κB activation), leading to increased osteoclast formation and bone resorption, as well as to attenuate Wnt signaling, leading to both decreased bone and increased marrow fat formation. In recent years, understanding the mechanisms of action and potential health benefits of selected nutraceuticals, including resveratrol, genistein, icariin, and inflammatory fatty acids, has led to preclinical studies that, in some cases, indicate efficacy in reducing chemotherapy-induced bone defects. We summarize the supporting evidence.
Effects of pyrite bioleaching solution of Acidithiobacillus ferrooxidans on viability, differentiation and mineralization potentials of rat osteoblasts
Publisher: Springer Science and Business Media LLC
Date: 18-08-2015
DOI: 10.1007/S12272-015-0650-3
Abstract: Iron pyrite, an important component of traditional Chinese medicine, has a poor solubility, bioavailability, and patient compliance due to a high dose required and associated side effects, all of which have limited its clinical applications and experimental studies on its action mechanisms in improving fracture healing. This study investigated Acidithiobacillus ferrooxidans (A.f)-bioleaching of two kinds of pyrites and examined bioactivities of the derived solutions in viability and osteogenic differentiation in rat calvarial osteoblasts. A.f bioleaching improved element contents (Fe, Mn, Zn, Cu, and Se) in the derived solutions and the solutions concentration-dependently affected osteoblast viability and differentiation. While the solutions had no effects at low concentrations and inhibited the osteoblast alkaline phosphatase (ALP) activity at high concentrations, they improved ALP activity at their optimal concentrations. The improved osteoblast differentiation and osteogenic function at optimal concentrations were also revealed by levels of ALP cytochemical staining, calcium deposition, numbers and areas of mineralized nodules formed, mRNA and protein expression levels of osteogenesis-related genes (osteocalcin, Bmp-2, Runx-2, and IGF-1), and Runx-2 nuclear translocation. Data from this study will be useful in offering new strategies for improving pyrite bioavailability and providing a mechanistic explanation for the beneficial effects of pyrite in improving bone healing.
The frequency window effect of sinusoidal electromagnetic fields in promoting osteogenic differentiation and bone formation involves extension of osteoblastic primary cilia and activation of protein k
Publisher: Wiley
Date: 23-04-2021
DOI: 10.1002/CBIN.11606
Abstract: Electromagnetic fields (EMFs) have emerged as a versatile means for osteoporosis treatment and prevention. However, its optimal application parameters are still elusive. Here, we optimized the frequency parameter first by cell culture screening and then by animal experiment validation. Osteoblasts isolated from newborn rats (ROBs) were exposed 90 min/day to 1.8 mT SEMFs at different frequencies (ranging from 10 to 100 Hz, interval of 10 Hz). SEMFs of 1.8 mT inhibited ROB proliferation at 30, 40, 50, 60 Hz, but increased proliferation at 10, 70, 80 Hz. SEMFs of 10, 50, and 70 Hz promoted ROB osteogenic differentiation and mineralization as shown by alkaline phosphatase (ALP) activity, calcium content, and osteogenesis‐related molecule expression analyses, with 50 Hz showing greater effects than 10 and 70 Hz. Treatment of young rats with 1.8 mT SEMFs at 10, 50, or 100 Hz for 2 months significantly increased whole‐body bone mineral density (BMD) and femur microarchitecture, with the 50 Hz group showing the greatest effect. Furthermore, 1.8 mT SEMFs extended primary cilia lengths of ROBs and increased protein kinase A (PKA) activation also in a frequency‐dependent manner, again with 50 Hz SEMFs showing the greatest effect. Pretreatment of ROBs with the PKA inhibitor KT5720 abolished the effects of SEMFs to increase primary cilia length and promote osteogenic differentiation/mineralization. These results indicate that 1.8 mT SEMFs have a frequency window effect in promoting osteogenic differentiation/mineralization in ROBs and bone formation in growing rats, which involve osteoblast primary cilia length extension and PKA activation.
Neurotrophins from dorsal root ganglia trigger allodynia after spinal nerve injury in rats
Publisher: Wiley
Date: 2000
DOI: 10.1046/J.1460-9568.2000.00884.X
Abstract: Injury to peripheral nerves often results in chronic pain which is difficult to relieve. The mechanism underlying the pain syndrome remains largely unknown. In previous studies we showed that neurotrophins are up-regulated in satellite cells around sensory neurons following sciatic nerve lesion. In the present study, we have examined whether the neurotrophins in the dorsal root ganglia play any role in allodynia after nerve injury. Antibodies to different neurotrophins, directly delivered to injured dorsal root ganglia, significantly reduced (with different time sequences) the percentage of foot withdrawal responses evoked by von Frey hairs. The antibodies to nerve growth factor acted during the early phase but antibodies to neurotrophin-3 and brain-derived neurotrophic factor were effective during the later phase. Exogenous nerve growth factor or brain-derived neurotrophic factor, but not neurotrophin-3, directly delivered to intact dorsal root ganglia, trigger a persistent mechanical allodynia. Our results showed that neurotrophins within the dorsal root ganglia after peripheral nerve lesion are involved in the generation of allodynia at different stages. These studies provide the first evidence that ganglia-derived neurotrophins are a source of nociceptive stimuli for neuropathic pain after peripheral nerve injury.
Lumbar 5 ventral root transection-induced upregulation of nerve growth factor in sensory neurons and their target tissues: A mechanism in neuropathic pain
Publisher: Elsevier BV
Date: 06-2003
DOI: 10.1016/S1044-7431(03)00062-9
Abstract: We have previously demonstrated that profound and persistent neuropathic pain as displayed by mechanical and cold allodynia and thermal hyperalgesia can be produced by a lumbar 5 ventral root transection (L5 VRT) model in adult rats in which only the motor nerve fibers were injured without axotomy of sensory neurons. However, the underlying mechanisms remain to be determined. In this study, by examining its changes in expression and by inhibiting its functions using a neutralizing antibody, we have investigated whether nerve growth factor (NGF), a neurotrophic factor known to have a function in regulating nerve injury-induced pain, is involved in the development of neuropathic pain induced by L5 VRT. Motor nerve injury by L5 VRT resulted in a de novo expression of NGF mRNA in a subpopulation of small sensory neurons and pericellular satellite cells in ipsilateral L5 dorsal root ganglion. NGF protein expression was also increased by sensory neurons with various sizes and by keratinocytes in the target tissue ipsilateral skin. Systemic administration of NGF antiserum twice within 17 days markedly attenuated L5 VRT-induced mechanical allodynia but not the cold allodynia and thermal hyperalgesia. These findings suggest that NGF is an important pain mediator in the generation of mechanical sensitivity induced by L5 VRT.
Strain amplification analysis of an osteocyte under static and cyclic loading: a finite element study.
Publisher: Hindawi Limited
Date: 2015
DOI: 10.1155/2015/376474
Abstract: Osteocytes, the major type of bone cells which reside in their lacunar and canalicular system within the bone matrix, function as biomechanosensors and biomechanotransducers of the bone. Although biomechanical behaviour of the osteocyte-lacunar-canalicular system has been investigated in previous studies mostly using computational 2-dimensional (2D) geometric models, only a few studies have used the 3-dimensional (3D) finite element (FE) model. In the current study, a 3D FE model was used to predict the responses of strain distributions of osteocyte-lacunar-canalicular system analyzed under static and cyclic loads. The strain lification factor was calculated for all simulations. Effects on the strain of the osteocyte system were investigated under 500, 1500, 2000, and 3000 microstrain loading magnitudes and 1, 5, 10, 40, and 100 Hz loading frequencies. The maximum strain was found to change with loading magnitude and frequency. It was observed that maximum strain under 3000-microstrain loading was higher than those under 500, 1500, and 2000 microstrains. When the loading strain reached the maximum magnitude, the strain lification factor of 100 Hz was higher than those of the other frequencies. Data from this 3D FE model study suggests that the strain lification factor of the osteocyte-lacunar-canalicular system increases with loading frequency and loading strain increasing.
Icariin attenuates hypoxia-induced oxidative stress and apoptosis in osteoblasts and preserves their osteogenic differentiation potential in vitro
Publisher: Wiley
Date: 30-10-2014
DOI: 10.1111/CPR.12147
<p>Hydrocortisone Suppresses Early Paraneoplastic Inflammation And Angiogenesis To Attenuate Early Hepatocellular Carcinoma Progression In Rats</p>
Publisher: Informa UK Limited
Date: 11-2019
DOI: 10.2147/OTT.S224618
Effects of 50Hz sinusoidal electromagnetic fields of different intensities on proliferation, differentiation and mineralization potentials of rat osteoblasts
Publisher: Elsevier BV
Date: 10-2011
DOI: 10.1016/J.BONE.2011.06.026
Abstract: Electromagnetic fields (EMFs) have been used clinically to slow down osteoporosis and promote fracture healing for many years. However, the underlying action mechanisms and optimal parameters of the EMF applications are unclear. In this study, we investigated the effects of treatment for different durations with 50 Hz sinusoidal electromagnetic fields (SEMFs) at different intensities on proliferation, differentiation and mineralization potentials of rat osteoblasts. Osteoblasts isolated from neonatal rats were treated with SEMFs (50 Hz at 0.9 mT-4.8 mT, 0.3 mT interval, 30 min/day up to 15 days). Compared to untreated control, SEMFs inhibited osteoblast proliferation (after 3 days' treatment) but increased alkaline phosphatase (ALP) activity (after treatment for 9 days) from 0.9 mT to 1.8 mT, declined from 1.8 mT until 3.0 mT, and then increased again from 3.0 mT to 3.6 mT and decreased once again from 3.6 mT to 4.8 mT. Numbers of colonies stained positive for ALP after 8 days and mineralized nodules stained by Alizarin red after 10 days showed the same bimodal tendency as with the ALP activity, with two peaks at 1.8 mT and 3.6 mT. SEMFs also bimodally increased Runx-2, Col1α2 and Bmp-2 mRNA expression levels in osteoblasts at 12, 24 and 96 h after exposure. The results indicated that while exposure to 50 Hz SEMFs inhibits the osteoblast proliferation, it significantly promotes differentiation and mineralization potentials of osteoblasts in an intensity-dependent manner with peak activity at 1.8 mT and 3.6 mT.
Corrigendum to Effects of 50Hz sinusoidal electromagnetic fields of different intensities on proliferation, differentiation and mineralization potentials of rat osteoblasts
Publisher: Elsevier BV
Date: 03-2012
FGF-2 Gene Polymorphism in Osteoporosis among Guangxi’s Zhuang Chinese
Publisher: MDPI AG
Date: 27-06-2017
DOI: 10.3390/IJMS18071358
Differential effects of endogenous brain-derived neurotrophic factor on the survival of axotomized sensory neurons in dorsal root ganglia: A possible role for the p75 neurotrophin receptor
Publisher: Elsevier BV
Date: 2005
DOI: 10.1016/J.NEUROSCIENCE.2004.12.034
Abstract: After peripheral nerve injury, axotomized sensory neurons in dorsal root ganglia (DRG) undergo apoptosis and up-regulate brain-derived neurotrophic factor (BDNF). We tested whether endogenous BDNF plays any role in the survival of axotomized sensory neurons using in vitro and in vivo models. In the in vitro model, treatment with BDNF antibody significantly reduced apoptosis of sensory neurons in DRG explants from both adult and neonate rats and adult mice cultured for 48 h. Consistently, exogenous BDNF increased the percentage of apoptotic neurons in the DRGs from mice. The effects of the BDNF antibody and BDNF were not seen in DRGs from p75NTR(-/-) mice. In the in vivo model, sciatic nerve transection in neonatal rats decreased the total number of neurons in the injured DRG and treatment with antiserum to BDNF significantly exaggerated the loss of DRG neurons. Numbers of sensory neurons expressing BDNF and p75NTR in cultured DRGs increased but that expressing TrkB decreased. In contrast, sciatic nerve transection in vivo reduced the numbers of neurons expressing both p75NTR and TrkB but increased the numbers of cells expressing BDNF, 1 and 7 days after the surgery. These results suggest that BDNF may have differential effects on the survival of sensory neurons depending on the expression of p75NTR. While endogenous BDNF induced apoptosis of axotomized sensory neurons through p75NTR in vitro where more neurons expressed p75NTR, it prevented apoptosis in vivo where fewer neurons expressed p75NTR after sciatic nerve transection.
Comparison of wheat germ agglutinin-horseradish peroxidase and biotinylated dextran for anterograde tracing of corticospinal tract following spinal cord injury
Publisher: Elsevier BV
Date: 08-2001
DOI: 10.1016/S0165-0270(01)00380-6
Abstract: Established methods for monitoring regeneration of the corticospinal tract involve anterograde labelling of the cortical motor neuron. While wheat germ agglutinin-horseradish peroxidase conjugate has been used to anterogradely label these neurons, we demonstrate that this technique may not completely label the whole axon and fine terminal processes when this tracer is administered in dried form. An alternative method is described for anterograde labelling of cortical motor neurons using biotinylated dextran. This tracer may be applied by either microinjection of 10% biotinylated dextran or implanting small globules of the dried tracer into the motor cortex. While more laborious, microinjection results in better anterograde labelling than implantation of dried biotinylated dextran. A procedure is also described for preparing serial coronal sections through the entire spinal cord and thaw-mounted on a minimum number of slides. The labelled nerve processes in these tissue sections can be visualised in the spinal cord under a fluorescent microscope following incubation with cy3-streptavidin complex. Permanent labelling of the biotinylated nerve processes is achieved by incubation of tissue sections with streptavidin-horseradish peroxidase conjugate followed by stringent washes and staining with tetramethylbenzidine. Use of tetramethylbenzidine allows resolution of a greater number of finer labelled processes than diaminobenzindine and allows clear visualisation of in idual regenerating corticospinal tract processes. Using these procedures, we demonstrate that the corticospinal tract is completely lesioned by a standardised contusion spinal cord injury produced by the New York University weight-drop device.
miR-142-5p in Bone Marrow-Derived Mesenchymal Stem Cells Promotes Osteoporosis Involving Targeting Adhesion Molecule VCAM-1 and Inhibiting Cell Migration
Publisher: Hindawi Limited
Date: 2018
DOI: 10.1155/2018/3274641
Abstract: Osteoporosis is a systemic bone metabolic disease that is highly prevalent in the elderly population, particularly in postmenopausal women, which results in enhanced bone fragility and an increased susceptibility to fractures. However, the underlying molecular pathogenesis mechanisms still remain to be further elucidated. In this study, in a rat ovariectomy- (OVX-) induced postmenopausal osteoporosis model, aberrant expression of a microRNA miR-142-5p and vascular cell adhesion molecule 1 (VCAM-1) was found by RNA sequencing analysis and qRT-PCR. Using a dual-luciferase reporter assay, we found that miR-142-5p can bind to and decrease expression of VCAM-1 mRNA. Such reduction was prohibited when the miR-142-5p binding site in VCAM-1 3′UTR was deleted, and Western blotting analyses validated the fact that miR-142-5p inhibited the expression of VCAM-1 protein. Bone marrow-derived mesenchymal stem cells (BMMSCs) transfected with miR-142-5p showed a significantly decreased migration ability in a Transwell migration assay. Collectively, these data indicated the important role of miR-142-5p in osteoporosis development involving targeting VCAM-1 and inhibiting BMMSC migration.
Pulsed electromagnetic fields promote osteoblast mineralization and maturation needing the existence of primary cilia
Publisher: Elsevier BV
Date: 03-2015
DOI: 10.1016/J.MCE.2015.01.031
Abstract: Although pulsed electromagnetic fields (PEMFs) have been approved as a therapy for osteoporosis, action mechanisms and optimal parameters are elusive. To determine the optimal intensity, exposure effects of 50 Hz PEMFs of 0.6-3.6 mT (0.6 interval at 90 min/day) were investigated on proliferation and osteogenic differentiation of cultured calvarial osteoblasts. All intensity groups stimulated proliferation significantly with the highest effect at 0.6 mT. The 0.6 mT group also obtained the optimal osteogenic effect as demonstrated by the highest ALP activity, ALP(+) CFU-f colony formation, nodule mineralization, and expression of COL-1 and BMP-2. To verify our hypothesis that the primary cilia are the cellular sensors for PEMFs, osteoblasts were also transfected with IFT88 siRNA or scrambled control, and osteogenesis-promoting effects of 0.6 mT PEMFs were found abrogated when primary cilia were inhibited by IFT88 siRNA. Thus primary cilia of osteoblasts play an indispensable role in mediating PEMF osteogenic effect in vitro.
RECENT RESEARCH ON THE GROWTH PLATE Mechanisms for growth plate injury repair and potential cell-based therapies for regeneration
Publisher: Bioscientifica
Date: 08-2014
DOI: 10.1530/JME-14-0062
Abstract: Injuries to the growth plate cartilage often lead to bony repair, resulting in bone growth defects such as limb length discrepancy and angulation deformity in children. Currently utilised corrective surgeries are highly invasive and limited in their effectiveness, and there are no known biological therapies to induce cartilage regeneration and prevent the undesirable bony repair. In the last 2 decades, studies have investigated the cellular and molecular events that lead to bony repair at the injured growth plate including the identification of the four phases of injury repair responses (inflammatory, fibrogenic, osteogenic and remodelling), the important role of inflammatory cytokine tumour necrosis factor alpha in regulating downstream repair responses, the role of chemotactic and mitogenic platelet-derived growth factor in the fibrogenic response, the involvement and roles of bone morphogenic protein and Wnt/B-catenin signalling pathways, as well as vascular endothelial growth factor-based angiogenesis during the osteogenic response. These new findings could potentially lead to identification of new targets for developing a future biological therapy. In addition, recent advances in cartilage tissue engineering highlight the promising potential for utilising multipotent mesenchymal stem cells (MSCs) for inducing regeneration of injured growth plate cartilage. This review aims to summarise current understanding of the mechanisms for growth plate injury repair and discuss some progress, potential and challenges of MSC-based therapies to induce growth plate cartilage regeneration in combination with chemotactic and chondrogenic growth factors and supporting scaffolds.
Low Night Temperature Affects the Phloem Ultrastructure of Lateral Branches and Raffinose Family Oligosaccharide (RFO) Accumulation in RFO-Transporting Plant Melon (Cucumismelo L.) during Fruit Expans
Publisher: Public Library of Science (PLoS)
Date: 08-08-2016
The Importance of the Prenyl Group in the Activities of Osthole in Enhancing Bone Formation and Inhibiting Bone Resorption In Vitro
Publisher: Hindawi Limited
Date: 2014
DOI: 10.1155/2014/921954
Abstract: Osteoporosis treatment always aimed at keeping the balance of bone formation and bone resorption. Recently, prenyl group in natural products has been proposed as an active group to enhance the osteogenesis process. Osthole has both the prenyl group and bone-protective activities, but the relationship is still unknown. In this study we found that osthole exerted a potent ability to promote proliferation and osteogenic function of rat bone marrow stromal cells and osteoblasts, including improved cell viability, alkaline phosphatase activity, enhanced secretion of collagen-I, bone morphogenetic protein-2, osteocalcin and osteopontin, stimulated mRNA expression of insulin-like growth factor-1, runt-related transcription factor-2, osterix, OPG (osteoprotegerin), RANKL (receptor activator for nuclear factor- κ B ligand), and the ratio of OPG/RANKL, as well as increasing the formation of mineralized nodules. However, 7-methoxycoumarin had no obvious effects. Osthole also inhibited osteoclastic bone resorption to a greater extent than 7-methoxycoumarin, as shown by a lower tartrate-resistant acid phosphatase activity and lower number and smaller area of resorption pits. Our findings demonstrate that osthole could be a potential agent to stimulate bone formation and inhibit bone resorption, and the prenyl group plays an important role in these bone-protective effects.
Functions and action mechanisms of flavonoids genistein and icariin in regulating bone remodeling
Publisher: Wiley
Date: 23-11-2013
DOI: 10.1002/JCP.24158
Abstract: Increasingly natural products particularly flavonoids are being explored for their therapeutic potentials in reducing bone loss and maintaining bone health. This study has reviewed previous studies on the two better known flavonoids, genistein and icariin, their structures, functions, action mechanisms, relative potency, and potential application in regulating bone remodeling and preventing bone loss. Genistein, an isoflavone abundant in soy, has dual functions on bone cells, able to inhibit bone resorption activity of osteoclasts and stimulate osteogenic differentiation and maturation of bone marrow stromal progenitor cells (BMSCs) and osteoblasts. Genistein is an estrogen receptor (ER)-selective binding phytoestrogen, with a greater affinity to ERβ. Genistein inhibits tyrosine kinases and inhibits DNA topoisomerases I and II, and may act as an antioxidant. Genistein enhances osteoblastic differentiation and maturation by activation of ER, p38MAPK-Runx2, and NO/cGMP pathways, and it inhibits osteoclast formation and bone resorption through inducing osteoclastogenic inhibitor osteoprotegerin (OPG) and blocking NF-κB signaling. Icariin, a prenylated flavonol glycoside isolated from Epimedium herb, stimulates osteogenic differentiation of BMSCs and inhibits bone resorption activity of osteoclasts. Icariin, whose metabolites include icariside I, icariside II, icaritin, and desmethylicaritin, has no estrogenic activity. However, icariin is more potent than genistein in promoting osteogenic differentiation and maturation of osteoblasts. The existence of a prenyl group on C-8 of icariin molecular structure has been suggested to be the reason why icariin is more potent than genistein in osteogenic activity. Thus, the prenylflavonoids may represent a class of flavonoids with a higher osteogenic activity.
Microtubule actin crosslinking factor 1 promotes osteoblast differentiation by promoting β‐catenin/TCF1/Runx2 signaling axis
Publisher: Wiley
Date: 03-08-2017
DOI: 10.1002/JCP.26059
Abstract: Osteoblast differentiation is a multistep process delicately regulated by many factors, including cytoskeletal dynamics and signaling pathways. Microtubule actin crosslinking factor 1 (MACF1), a key cytoskeletal linker, has been shown to play key roles in signal transduction and in erse cellular processes however, its role in regulating osteoblast differentiation is still needed to be elucidated. To further uncover the functions and mechanisms of action of MACF1 in osteoblast differentiation, we examined effects of MACF1 knockdown (MACF1‐KD) in MC3T3‐E1 osteoblastic cells on their osteoblast differentiation and associated molecular mechanisms. The results showed that knockdown of MACF1 significantly suppressed mineralization of MC3T3‐E1 cells, down‐regulated the expression of key osteogenic genes alkaline phosphatase (ALP), runt‐related transcription factor 2 (Runx2) and type I collagen α1 (Col Iα1). Knockdown of MACF1 dramatically reduced the nuclear translocation of β‐catenin, decreased the transcriptional activation of T cell factor 1 (TCF1), and down‐regulated the expression of TCF1, lymphoid enhancer‐binding factor 1 (LEF1), and Runx2, a target gene of β‐catenin/TCF1. In addition, MACF1‐KD increased the active level of glycogen synthase kinase‐3β (GSK‐3β), which is a key regulator for β‐catenin signal transduction. Moreover, the reduction of nuclear β‐catenin amount and decreased expression of TCF1 and Runx2 were significantly reversed in MACF1‐KD cells when treated with lithium chloride, an agonist for β‐catenin by inhibiting GSK‐3β activity. Taken together, these findings suggest that knockdown of MACF1 in osteoblastic cells inhibits osteoblast differentiation through suppressing the β‐catenin/TCF1‐Runx2 axis. Thus, a novel role of MACF1 in and a new mechanistic insight of osteoblast differentiation are uncovered.
Flavonoid genistein protects bone marrow sinusoidal blood vessels from damage by methotrexate therapy in rats
Publisher: Wiley
Date: 22-11-2018
DOI: 10.1002/JCP.27785
Abstract: Cancer chemotherapy can cause significant damage to the bone marrow (BM) microvascular (sinusoidal) system. Investigations must now address whether and how BM sinusoidal endothelial cells (SECs) can be protected during chemotherapy. Herein we examined the potential protective effects of genistein, a soy‐derived flavonoid, against BM sinusoidal damage caused by treatment with methotrexate (MTX). The groups of young adult rats were gavaged daily with genistein (20 mg/kg) or placebo. After 1 week, rats also received daily injections of MTX (0.75 mg/kg) or saline for 5 days and were killed after a further 4 days. Histological analyses showed that BM sinusoids were markedly dilated ( p 0.001) in the MTX‐alone group but were unaffected or less dilated in the genistein+MTX group. In control rats, genistein significantly enhanced expression of vascular endothelial growth factor (VEGF p 0.01), particularly in osteoblasts, and angiogenesis marker CD31 ( p 0.001) in bone. In MTX‐treated rats, genistein suppressed MTX‐induced apoptosis of BM SECs ( p 0.001 vs MTX alone group) and tended to increase expression of CD31 and VEGF ( p 0.05). Our in vitro studies showed that genistein in certain concentrations protected cultured SECs from MTX cytotoxic effects. Genistein enhanced tube formation of cultured SECs, which is associated with its ability to induce expression of endothelial nitric oxide synthase and production of nitric oxide. These data suggest that genistein can protect BM sinusoids during MTX therapy, which is associated, at least partially, with its indirect effect of promoting VEGF expression in osteoblasts and its direct effect of enhancing nitric oxide production in SECs.
Satellite-cell-derived nerve growth factor and neurotrophin-3 are involved in noradrenergic sprouting in the dorsal root ganglia following peripheral nerve injury in the rat.
Publisher: Wiley
Date: 05-1999
DOI: 10.1046/J.1460-9568.1999.00589.X
Abstract: Injury to a peripheral nerve induces in the dorsal root ganglia (DRG) sprouting of sympathetic and peptidergic terminals around large-diameter sensory neurons that project in the damaged nerve. This pathological change may be implicated in the chronic pain syndromes seen in some patients with peripheral nerve injury. The mechanisms underlying the sprouting are not known. Using in situ hybridization and immunohistochemical techniques, we have now found that nerve growth factor (NGF) and neurotrophin-3 (NT3) synthesis is upregulated in satellite cells surrounding neurons in lesioned DRG as early as 48 h after nerve injury. This response lasts for at least 2 months. Quantitative analysis showed that the levels of mRNAs for NT3 and NGF increased in ipsilateral but not contralateral DRG after nerve injury. Noradrenergic sprouting around the axotomized neurons was associated with p75-immunoreactive satellite cells. Further, antibodies specific to NGF or NT3, delivered by an osmotic mini-pump to the DRG via the lesioned L5 spinal nerve, significantly reduced noradrenergic sprouting. These results implicate satellite cell-derived neurotrophins in the induction of sympathetic sprouting following peripheral nerve injury.
Microengineered 3D cell-laden thermoresponsive hydrogels for mimicking cell morphology and orientation in cartilage tissue engineering
Publisher: Wiley
Date: 09-08-2016
DOI: 10.1002/BIT.26061
Abstract: Mimicking the zonal organization of native articular cartilage, which is essential for proper tissue functions, has remained a challenge. In this study, a thermoresponsive copolymer of chitosan-g-poly(N-isopropylacrylamide) (CS-g-PNIPAAm) was synthesized as a carrier of mesenchymal stem cells (MSCs) to provide a support for their proliferation and differentiation. Microengineered three-dimensional (3D) cell-laden CS-g-PNIPAAm hydrogels with different microstripe widths were fabricated to control cellular alignment and elongation in order to mimic the superficial zone of natural cartilage. Biochemical assays showed six- and sevenfold increment in secretion of glycosaminoglycans (GAGs) and total collagen from MSCs encapsulated within the synthesized hydrogel after 28 days incubation in chondrogenic medium. Chondrogenic differentiation was also verified qualitatively by histological and immunohistochemical assessments. It was found that 75 ± 6% of cells encapsulated within 50 μm wide microstripes were aligned with an aspect ratio of 2.07 ± 0.16 at day 5, which was more organized than those observed in unpatterned constructs (12 ± 7% alignment and a shape index of 1.20 ± 0.07). The microengineered constructs mimicked the cell shape and organization in the superficial zone of cartilage whiles the unpatterned one resembled the middle zone. Our results suggest that microfabrication of 3D cell-laden thermosensitive hydrogels is a promising platform for creating biomimetic structures leading to more successful multi-zonal cartilage tissue engineering. Biotechnol. Bioeng. 2017 : 217-231. © 2016 Wiley Periodicals, Inc.
Cellular mechanisms for methotrexate chemotherapy-induced bone growth defects
Publisher: Elsevier BV
Date: 11-2007
DOI: 10.1016/J.BONE.2007.07.021
Abstract: Methotrexate (MTX) is a commonly used anti-metabolite in childhood oncology and is known to cause bone growth arrest and osteoporosis yet the underlying mechanisms for MTX-induced bone growth defects remain largely unclear. This study characterized damaging effects in young rats of acute chemotherapy with 5 once-daily doses of MTX (0.75 mg/kg) on the cellular activities in the growth plate in producing calcified cartilage and trabecular bone and on activities of osteoblastic cells in the metaphysis. MTX treatment significantly induced chondrocyte apoptosis. MTX also suppressed chondrocyte proliferation and reduced collagen-II mRNA expression and total thickness of the growth plate, with the damage being most obvious on day 9 after the first injection, and with the growth plate histological structure returning normal on day 14. In the adjacent metaphyseal bone, mirroring the decrease in the width of the growth plate, production of primary spongiosa bone was markedly reduced and bone volume of the secondary spongiosa was decreased. Furthermore, MTX treatment significantly induced osteocyte apoptosis in the primary spongiosa and reduced proliferation of osteoblasts and preosteoblasts particularly in the secondary spongiosa. These observations suggest that methotrexate chemotherapy may cause bone growth defects by arresting cellular activities in the growth plate in producing calcified cartilage and primary trabecular bone and by decreasing pools of metaphyseal osteoblastic cells. However, this short-term MTX treatment only caused transit suppressions on growth plate cartilage and trabecular bone, as most cellular and histological parameters had recovered by day 14 or 21.
Methotrexate chemotherapy triggers touch-evoked pain and increased CGRP-positive sensory fibres in the tibial periosteum of young rats
Publisher: Elsevier BV
Date: 04-2015
DOI: 10.1016/J.BONE.2014.11.022
Abstract: Although bone pain caused by cancer chemotherapy is a well-recognized and significant problem, with approximately 1 in 10 childhood cancer patients being reported to experience isolated bone pain along with other skeletal complications, the underlying mechanisms are poorly understood and there is no specific treatment. In this study, effects of methotrexate (MTX) treatment on pain in the hind legs and the extent of sensory innervation of the tibial bone were examined through a 20-day time course in young rats after 5 daily 0.75 mg/kg MTX injections. MTX treatment increased von-Frey filament stimulation-induced mechanical allodynia and palpation nocifensive score in the tibia. MTX-treated rats showed trends in reduced loading (numbers of stands) on hind limbs after palpation, commencing early during treatment and 2 weeks after the end of treatment despite no signs of ongoing pain during normal locomotion. Immunohistochemical analyses showed an increase in innervation of calcitonin gene-related peptide (CGRP)-positive sensory nerve fibres in tibial periosteum on days preceding and overlapping with those rats with touch-evoked pain responses and the bone repair phase. These data suggest that methotrexate chemotherapy triggers touch-evoked pain involving enhanced sensory nerve innervation of the bone.
TNF-α mediates p38 MAP kinase activation and negatively regulates bone formation at the injured growth plate in rats
Publisher: Wiley
Date: 15-05-2006
DOI: 10.1359/JBMR.060410
Abstract: TNF-alpha is known to inhibit osteoblast differentiation in vitro and yet it is essential for bone fracture repair. Roles of TNF-alpha in the bony repair of injured growth plate were examined in young rats treated with a TNF-alpha antagonist. The results show that TNF-alpha mediates p38 activation, which influences the recruitment, proliferation, and osteoblast differentiation of mesenchymal cells and negatively regulates bone formation at the injured growth plate. TNF-alpha inhibits expression of osteoblast differentiation factor cbfa1 and osteoblast differentiation in vitro and yet TNF-alpha signaling is essential for bone fracture healing. Roles of TNF-alpha in the bony repair of injured growth plate cartilage are unknown. Roles of TNF-alpha in the activation of p38 mitogen activated protein (MAP) kinase and the subsequent bony repair of the injured growth plate were examined in young rats receiving the TNF-alpha inhibitor ENBREL or saline control. Activation of p38 was determined by Western blot analysis and immunohistochemistry. Inflammatory cell counts on day 1, measurements of repair tissue proportions, and counting of proliferative mesenchymal cells on day 8 at growth plate injury site were carried out (n = 6). Expression of inflammatory cytokines TNF-alpha and IL-1beta, fibrogenic growth factor (FGF)-2, cbfa1, and bone protein osteocalcin at the injured growth plate was assessed by quantitative RT-PCR. Effects of TNF-alpha signaling on proliferation, migration, and apoptosis of rat bone marrow mesenchymal cells (rBMMCs) and the regulatory roles of p38 in these processes were examined using recombinant rat TNF-alpha, ENBREL, and the p38 inhibitor SB239063 in cultured primary rBMMCs. p38 activation was induced in the injured growth plate during the initial inflammatory response, and activated p38 was immunolocalized in inflammatory cells at the injury site and in the adjacent growth plate. In addition, activation of p38 was blocked in rats treated with TNF-alpha antagonist, suggesting a role of TNF-alpha in p38 activation. Whereas TNF-alpha inhibition did not alter inflammatory infiltrate and expression of TNF-alpha and IL-1beta at the injured growth plate on day 1, it reduced mesenchymal infiltrate and cell proliferation and FGF-2 expression on day 8. Consistently, TNF-alpha increased proliferation and migration of rBMMCs in vitro, whereas p38 inhibition reduced rBMMC proliferation and migration. At the injured growth plate on day 8, TNF-alpha inhibition increased expression of cbfa1 and osteocalcin and increased trabecular bone formation at the injury site. There was a significant inverse correlation between TNF-alpha and cbfa1 expression levels, suggesting a negative relationship between TNF-alpha and cbfa1 in this in vivo model. These observations suggest that TNF-alpha activates p38 MAP kinase during the inflammatory response at the injured growth plate, and TNF-alpha-p38 signaling seems to be required for marrow mesenchymal cell proliferation and migration at the growth plate injury site and in cell culture. Furthermore, TNF signaling has an inhibitory effect on bone formation at the injured growth plate by suppressing bone cell differentiation and bone matrix synthesis at the injury site.
Site-Specific Changes in Transforming Growth Factor-a and -ß1 Expression in Colonic Mucosa of Adolescents with Inflammatory Bowel Disease
Publisher: Informa UK Limited
Date: 1999
DOI: 10.1080/003655299750026056
Abstract: Transforming growth factors (TGF-alpha and -beta1) play important roles in intestinal growth and repair. To further understand their roles in the pathophysiology of inflammatory bowel disease (IBD), this study examined changes in their expression in colonic mucosa of adolescents with IBD. TGF-alpha and -beta1 expression was examined by immunohistochemistry and in situ hybridization. TGF-gamma immunostaining and mRNA labelling appeared unchanged in the epithelium of specimens with active IBD. Similarly, expression of epithelial TGF-beta1 remained unaltered in IBD. However, the numbers of TGF-beta1-positive cells, including T cells, neutrophils, and monocytes/macrophages, in the lamina propria increased during disease activity. Adolescent IBD is characterized by a normal expression of TGF-alpha and -beta1 peptide and mRNA in the colonic epithelium but by an increased density of TGF-beta1-positive immune cells in the lamina propria during disease activity, suggesting a role in inflammatory modulation in IBD.
Inhibition of protein kinase-D promotes cartilage repair at injured growth plate in rats
Publisher: Elsevier BV
Date: 07-2013
DOI: 10.1016/J.INJURY.2013.01.038
Abstract: Injured growth plate cartilage is often repaired by bony tissue, causing bone growth defects in children. Currently, mechanisms for the undesirable repair remain unclear and there are no biological treatments available to prevent the associated bone growth defects. Osterix is known as a vital transcription factor for osteoblast differentiation which is critical for normal bone formation and bone repair, and osterix is known to be regulated by protein kinase-D however it is unknown whether protein kinase-D-osterix signalling plays any roles in the bony repair of injured growth plate. Using a rat model, this study investigated potential roles of protein kinase-D (PKD) in regulating expression of osteogenic transcription factor osterix and the growth plate bony repair. 4 days post injury at the proximal tibial growth plate, rats received four once-daily injections of vehicle or 2.35 mg/kg gö6976 (a PKD inhibitor), and growth plate tissues collected at day 10 were examined histologically and molecularly. In addition, effects of PKD inhibition on osteogenic and chondrogenic differentiation were examined in vitro using rat bone marrow mesenchymal stromal cells. Compared to vehicle control, PKD inhibition caused a decrease in bone volume (p<0.05), an increase in % of mesenchymal tissue (p<0.01), and an increase in cartilaginous tissue within the injury site. Consistently, gö6976 treatment tended to decrease expression of bone-related genes (osterix, osteocalcin) and increase levels of cartilage-related genes (Sox9, collagen-2a, collagen-10a1). In support, in vitro experiments showed that gö6976 presence in the primary rat marrow stromal cell culture resulted in a decrease of alkaline phosphatase(+) CFU-f colonies formed (p<0.05) and an increase in collagen-2a expression in chondrogenic pellet culture (p<0.05). These studies suggest that PKD is important for growth plate bony repair and its inhibition after growth plate injury may result in less bone formation and potentially more cartilage repair.
Simulated microgravity‐induced oxidative stress and loss of osteogenic potential of osteoblasts can be prevented by protection of primary cilia
Publisher: Wiley
Date: 05-10-2023
DOI: 10.1002/JCP.31127
Blocking PI3K/AKT signaling inhibits bone sclerosis in subchondral bone and attenuates post‐traumatic osteoarthritis
Publisher: Wiley
Date: 07-03-2018
DOI: 10.1002/JCP.26460
Abstract: PI3K/AKT signaling is essential in regulating pathophysiology of osteoarthritis (OA). However, its potential modulatory role in early OA progression has not been investigated yet. Here, a mouse destabilization OA model in the tibia was used to investigate roles of PI3K/AKT signaling in the early subchondral bone changes and OA pathological process. We revealed a significant increase in PI3K/AKT signaling activation which was associated with aberrant bone formation in tibial subchondral bone following destabilizing the medial meniscus (DMM), which was effectively prevented by treatment with PI3K/AKT signaling inhibitor LY294002. PI3K/AKT signaling inhibition attenuated articular cartilage degeneration. Serum and bone biochemical analyses revealed increased levels of MMP‐13, which was found expressed mainly by osteoblastic cells in subchondral bone. However, this MMP‐13 induction was attenuated by LY294002 treatment. Furthermore, PI3K/AKT signaling was found to enhance preosteoblast proliferation, differentiation, and expression of MMP‐13 by activating NF‐κB pathway. In conclusion, inhibition of PI3K/AKT/NF‐κB axis was able to prevent aberrant bone formation and attenuate cartilage degeneration in OA mice.
Roles of apoptotic chondrocyte-derived CXCL12 in the enhanced chondroclast recruitment following methotrexate and/or dexamethasone treatment
Publisher: Wiley
Date: 12-01-2021
DOI: 10.1002/JCP.30278
Abstract: Intensive use of methotrexate (MTX) and/or dexamethasone (DEX) for treating childhood malignancies is known to cause chondrocyte apoptosis and growth plate dysfunction leading to bone growth impairments. However, mechanisms remain vague and it is unclear whether MTX and DEX combination treatment could have additive effects in the growth plate defects. In this study, significant cell apoptosis was induced in mature ATDC5 chondrocytes after treatment for 48 h with 10 −5 M MTX and/or 10 −6 M DEX treatment. PCR array assays with treated cells plus messenger RNA and protein expression confirmation analyses identified chemokine CXCL12 having the most prominent induction in each treatment group. Conditioned medium from treated chondrocytes stimulated migration of RAW264.7 osteoclast precursor cells and formation of osteoclasts, and these stimulating effects were inhibited by the neutralizing antibody for CXCL12. Additionally, while MTX and DEX combination treatment showed some additive effects on apoptosis induction, it did not have additive or counteractive effects on CXCL12 expression and its functions in enhancing osteoclastic recruitment and formation. In young rats treated acutely with MTX, there was increased expression of CXCL12 in the tibial growth plate, and more resorbing chondroclasts were found present at the border between the hypertrophic growth plate and metaphysis bone. Thus, the present study showed an association between induced chondrocyte apoptosis and stimulated osteoclastic migration and formation following MTX and/or DEX treatment, which could be potentially or at least partially linked molecularly by CXCL12 induction. This finding may contribute to an enhanced mechanistic understanding of bone growth impairments following MTX and/or DEX therapy.
Identification of a New Marine Bacterial Strain SD8 and Optimization of Its Culture Conditions for Producing Alkaline Protease
Publisher: Public Library of Science (PLoS)
Date: 30-12-2015
Roles of Wnt/β-catenin signalling pathway in the bony repair of injured growth plate cartilage in young rats
Publisher: Elsevier BV
Date: 02-2013
DOI: 10.1016/J.BONE.2012.10.035
Abstract: Growth plate cartilage is responsible for longitudinal growth of the long bone in children, and its injury is often repaired by bony tissue, which can cause limb length discrepancy and/or bone angulation deformities. Whilst earlier studies with a rat growth plate injury repair model have identified inflammatory, mesenchymal infiltration, osteogenesis and remodeling responses, the molecular mechanisms involved in the bony repair remain unknown. Since our recent microarray study has strongly suggested involvement of Wnt-β-catenin signalling pathway in regulating the growth plate repair and the pathway is known to play a crucial role in the osteogenic differentiation of mesenchymal progenitor cells, the current study investigated the potential roles of Wnt-β-catenin signalling pathway in the bony repair of injured tibial growth plate in rats. Immunohistochemical analysis of the growth plate injury site revealed β-catenin immunopositive cells within the growth plate injury site. Treatment of the injured rats with the β-catenin inhibitor ICG-001 (oral gavage at 200mg/kg/day for 8days, commenced at day 2 post injury) enhanced COL2A1 gene expression (by qRT-PCR) and increased proportion of cartilage tissue (by histological analysis), but decreased level of osterix expression and amount of bone tissue, at the injury site by day 10 post-injury (n=8, P<0.01 compared to vehicle controls). Consistently, in vitro studies with bone marrow stromal cells from normal rats showed that β-catenin inhibitor ICG-001 dose dependently inhibited expression of Wnt target genes Cyclin D1 and survivin (P<0.01). At 25mM, ICG-001 suppressed osteogenic (by CFU-f-ALP assay) but enhanced chondrogenic (by pellet culture) differentiation. These results suggest that Wnt/β-catenin signalling pathway is involved in regulating growth plate injury repair by promoting osteoblastogenesis, and that intervention of this signalling could represent a potential approach in enhancing cartilage repair after growth plate injury.
Adipose-derived stem cells seeded in Pluronic F-127 hydrogel promotes diabetic wound healing
Publisher: Elsevier BV
Date: 09-2017
DOI: 10.1016/J.JSS.2017.04.032
Abstract: Chronic nonhealing wound is a multifactorial complication of diabetes that results specifically as a consequence of impaired angiogenesis and currently lacks in effective treatments. Although a stem cell-based therapy may provide a novel treatment to augment diabetic wound healing, inferior cell survival at the diabetic skin wound is one of the key causes that are responsible for the low efficacy of the stem cell therapy. In this work, we used an injectable, biocompatible, and thermosensitive hydrogel Pluronic F-127 to encapsulate allogeneic nondiabetic adipose-derived stem cells (ADSCs) and topically applied the cells to a full-thickness cutaneous wound in the streptozotocin-induced diabetic model in rats. The cells seeded in the hydrogel enhanced angiogenesis (CD31 marker) and promoted the cell proliferation (Ki67 marker) at the wound site and significantly accelerated wound closure, which was accompanied by facilitated regeneration of granulation tissue. Consistently, levels of the messenger RNA expression of key angiogenesis growth factor, vascular endothelial growth factor, and key wound healing growth factor, transforming growth factor beta 1, were also upregulated in the cell-treated wounds when compared with untreated wounds. The results indicated that the transplantation of allogeneic ADSCs via the hydrogel improves the efficiency of cell delivery and optimizes the performance of ADSCs for augmenting diabetic wound healing. In conclusion, this ADSC-based therapy may provide a novel therapeutic strategy for the treatment of nonhealing diabetic foot ulcers.
Effects of maternal hypoxia during pregnancy on bone development in offspring: A guinea pig model
Publisher: Hindawi Limited
Date: 2014
DOI: 10.1155/2014/916918
Abstract: Low birth weight is associated with reduced bone mass and density in adult life. However, effects of maternal hypoxia (MH) on offspring bone development are not known. Objective . The current study investigated the effects of fetal growth restriction induced by MH during the last half of gestation on bone structure and volume in the offspring of the fetus near term and the pup in adolescence. Methods . During 35–62-day gestation (term, 69d), guinea pigs were housed in room air (21% O 2 control) or 12% O 2 (MH). Offspring femur and tibia were collected at 62d gestation and 120d after birth. Results . MH decreased fetal birth weight but did not affect osteogenic potential pools in the fetal bone marrow. Histological analysis showed no effects of MH on tibial growth plate thickness in either fetal or postnatal offspring, although there was increased VEGF mRNA expression in the growth plate of postnatal offspring. MH did not change primary spongiosa height but lowered collagen-1 mRNA expression in postnatal offspring. There was increased mRNA expression of adipogenesis-related gene (FABP4) in bone from the MH postnatal offspring. Conclusion . MH during late gestation did not change the pool of osteogenic cells before birth or growth plate heights before and after birth. However, MH reduced expression of bone formation marker (collagen-1) and increased expression of fat formation marker (FABP4) in postnatal offspring bone.
EGFL7 Is Expressed in Bone Microenvironment and Promotes Angiogenesis via ERK, STAT3, and Integrin Signaling Cascades
Publisher: Wiley
Date: 29-09-2014
DOI: 10.1002/JCP.24684
Abstract: Angiogenesis plays a pivotal role in bone formation, remodeling, and fracture healing. The regulation of angiogenesis in the bone microenvironment is highly complex and orchestrated by intercellular communication between bone cells and endothelial cells. Here, we report that EGF-like domain 7 (EGFL7), a member of the epidermal growth factor (EGF) repeat protein superfamily is expressed in both the osteoclast and osteoblast lineages, and promotes endothelial cell activities. Addition of exogenous recombinant EGFL7 potentiates SVEC (simian virus 40-transformed mouse microvascular endothelial cell line) cell migration and tube-like structure formation in vitro. Moreover, recombinant EGFL7 promotes angiogenesis featuring web-like structures in ex vivo fetal mouse metatarsal angiogenesis assay. We show that recombinant EGFL7 induces phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), signal transducer and activator of transcription 3 (STAT3), and focal adhesion kinase (FAK) in SVEC cells. Inhibition of ERK1/2 and STAT3 signaling impairs EGFL7-induced endothelial cell migration, and angiogenesis in fetal mouse metatarsal explants. Bioinformatic analyses indicate that EGFL7 contains a conserved RGD/QGD motif and EGFL7-induced endothelial cell migration is significantly reduced in the presence of RGD peptides. Moreover, EGFL7 gene expression is significantly upregulated during growth plate injury repair. Together, these results demonstrate that EGFL7 expressed by bone cells regulates endothelial cell activities through integrin-mediated signaling. This study highlights the important role that EGFL7, like EGFL6, expressed in bone microenvironment plays in the regulation of angiogenesis in bone.
Icariin is more potent than genistein in promoting osteoblast differentiation and mineralization in vitro
Publisher: Wiley
Date: 16-02-2011
DOI: 10.1002/JCB.23007
Abstract: There has been a strong interest in searching for natural therapies for osteoporosis. Genistein, an isoflavone abundant in soy, and icariin, a prenylated flavonol glycoside isolated from Epimedium Herb, have both been identified to exert beneficial effects in preventing postmenopausal bone loss. However, the relative potency in osteogenesis between the in idual phytoestrogen flavonoids remains unknown. The present study compared ability of genistein and icariin in enhancing differentiation and mineralization of cultured rat calvarial osteoblasts in vitro. Dose-dependent studies in osteoblast differentiation measuring alkaline phosphatase (ALP) activity revealed optimal concentrations of genistein and icarrin for stimulating osteogenesis to be both at 10(-5) M. Time course studies comparing the two compounds both at 10(-5) M demonstrated that icariin treatment always produced higher ALP activity, more and larger areas of CFU-F(ALP) colonies and mineralized nodules, more osteocalcin secretion, and calcium deposition, and a higher level of mRNA expression of osteogenesis-related genes COL1α2, BMP-2, OSX, and RUNX-2. However, they inhibited the proliferation of osteoblasts to a similar degree. In conclusion, although future in vivo studies are required to investigate whether icariin is more efficient in improving bone mass and/or preventing bone loss, our in vitro studies have demonstrated that icariin has a stronger osteogenic activity than genistein. In addition, while the prenyl group on C-8 of icariin could be the active group that takes part in osteoblastic differentiation and explains its greater potency in osteogenesis, mechanisms of action, and reasons for the relative potency of icariin versus genistein need to be further studied.
p16 deficiency attenuates intervertebral disc degeneration by adjusting oxidative stress and nucleus pulposus cell cycle
Publisher: eLife Sciences Publications, Ltd
Date: 03-03-2020
DOI: 10.7554/ELIFE.52570
Abstract: The cell cycle regulator p16 is known as a biomarker and an effector of aging. However, its function in intervertebral disc degeneration (IVDD) is unclear. In this study, p16 expression levels were found to be positively correlated with the severity of human IVDD. In a mouse tail suspension (TS)-induced IVDD model, lumbar intervertebral disc height index and matrix protein expression levels were reduced significantly were largely rescued by p16 deletion. In TS mouse discs, reactive oxygen species levels, proportions of senescent cells, and the senescence-associated secretory phenotype (SASP) were all increased, cell cycling was delayed, and expression was downregulated for Sirt1, superoxide dismutase 1/2, cyclin-dependent kinases 4/6, phosphorylated retinoblastoma protein, and transcription factor E2F1/2. However, these effects were rescued by p16 deletion. Our results demonstrate that p16 plays an important role in IVDD pathogenesis and that its deletion attenuates IVDD by promoting cell cycle and inhibiting SASP, cell senescence, and oxidative stress.
Potential roles of growth factor PDGF-BB in the bony repair of injured growth plate
Publisher: Elsevier BV
Date: 05-2009
DOI: 10.1016/J.BONE.2009.01.377
Abstract: Injured growth plate cartilage is often repaired by bony tissue resulting in impaired bone growth in children. Using a rat injury model, our previous studies show that following the injury-induced initial inflammatory response, an influx of mesenchymal-like cells occurs within the growth plate injury site prior to formation of bony tissue. As platelet-derived growth factor (PDGF-BB) is a potent chemotactic factor of mesenchymal cells during skeletal tissue repair, we examined its role during the early fibrogenic response and the subsequent bony repair of injured growth plate. Following growth plate injury, rats received daily injection of the PDGF receptor (PDGFR) inhibitor, Imatinib, for 7 days. Immunohistochemical analysis of injured growth plate at day 1 showed the presence of PDGF-BB expression in some inflammatory cells, while at day 4 PDGFR was expressed by a proportion of the infiltrating mesenchymal cells at the injury site. By day 4, PDGFR inhibition reduced mesenchymal infiltrate (P<0.05) by day 14, Imatinib-treated rats exhibited less bony trabeculae and cartilaginous repair tissues, fewer osteoclasts and less bone marrow (BM) at the injury site, compared to vehicle controls (P<0.01). In vitro "scratch" migration assays with rat BM mesenchymal cells revealed that recombinant PDGF-BB increased cell migration into the "wound" (P<0.05), while Imatinib inhibited this chemotactic response. Quantitative RT-PCR analysis showed that Imatinib treatment decreased expression of the cartilage and bone related genes, Col2a1 and osteocalcin, respectively. These results suggest that PDGF-BB contributes to growth plate injury repair by promoting mesenchymal progenitor cell infiltration, the chondrogenic and osteogenic responses, and remodelling of the repair tissues.
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