Male infertility and defective sperm-oocyte interaction

Funded Activity Summary

Infertility affects 15% of people and although not usually ill, they are extremely distressed by the condition. In vitro fertilisation (IVF) with normal sperm and intracytoplasmic sperm injection for sperm defects, can assist such patients have a family, but these treatments are expensive and not always successful. The causes of male infertility are largely unknown, diagnostic methods are crude and there is usually no treatment to promote natural conception. Conventional semen analysis provides limited information on fertilising ability. Our work over 15 years has shown that many patients go undiagnosed, particularly those with defects impairing fertilisation. During human fertilisation, sperm bind to the zona pellucida, a coat around the egg, via the membrane over a cap like structure on the sperm head called the acrosome. Binding of a sperm triggers the acrosome reaction, the process by which the membranes covering the acrosome fuse and the acrosomal contents are released. The sperm then penetrates the zona pellucida, binds to the membrane of the egg and is taken into the cytoplasm. We have developed tests to assess sperm binding to the zona pellucida and the acrosome reaction using eggs that failed to fertilise during clinical IVF. These tests show defects of sperm binding to the zona pellucida and the zona pellucida induced acrosome reaction are present in over 25% of patients without other obvious causes for their infertility. The men are severely infertile but have normal sperm by conventional tests. In this project we will determine if there are changes in membrane proteins in sperm which do not bind to the zona pellucida or undergo the acrosome reaction. We will categorise patients on the responses of their sperm to activation of key enzymes and other regulatory molecules involved in the fertilisation process. This will allow us to select subjects for further examination of protein abnormalities and genetic causes of the conditions.

Funded Activity Details

Start Date: 01-01-2006

End Date: 01-01-2008

Funding Scheme: NHMRC Project Grants

Funding Amount: $244,614.00

Funder: National Health and Medical Research Council

Research Topics

ANZSRC Field of Research (FoR)

Reproduction

ANZSRC Socio-Economic Objective (SEO)

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Other Keywords

Assisted reproductive technology | Male infertility | Male reproduction | Molecular mechanisms | Semen analysis | acrosome reaction | human gamete interaction

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