Research

1. Molecular interactions during fertilization
2. Sperm functional capacity in relationship to sperm fertility
3. Environmental toxicant induced changes in rat sperm-oocyte interaction

1. Molecular Interactions During Fertilization

Although much progress has been made in our understanding of the fertilization process, the molecular events in the fertilization process are still not understood to any great extent.

The focus in this area is to identify and characterize molecules in the sperm plasma membrane involved in interaction with the oocyte plasma membrane and the zona pellucida and molecules in the oocyte plasma membrane involved in interaction with the sperm plasma membrane.

This work involves membrane isolation, electrophoresis, ligand blotting, antibody procedures, confocal microscopy, sequencing, oocyte maturation, sperm capacitation, in vitro fertilization and other sperm-oocyte interaction assays.

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  2. Sperm Functional Capacities in Relationship to Sperm Fertilizing Ability

Exploring the steps in the fertilization process that are most likely to fail and hence contribute to fertilization failures, provides a logical basis for further refinement of in vitro sperm fertility assessments and may contribute to gamete preservation techniques.

Work in our laboratory has typically compared the relative performance of sperm from two ejaculates at a time in in vitro tests designed to simulate steps in the fertilization process with the percentage of offspring sired by each male when equal numbers of sperm are mixed and inseminated in vivo.

3. Environmental Toxicant-Induced Changes in Sperm-Oocyte Interaction

In vitro sperm-oocyte interaction may provide a more sensitive biomarker for reproductive toxicants. The hypothesis for this work is that sperm-oocyte interaction assays and study of the molecules involved in these interactions may provide sensitive biomarkers for reproductive toxicants. At the same time, manipulation of sperm-oocyte interaction capability with toxicants may provide an excellent model system to study the sperm and oocyte molecules involved in the interaction.

Protocols for rat in vitro fertilization have been established and the system tested with two model reproductive toxicants. Sperm plasma membrane isolation and ligand blotting have also been adapted to the rat sperm system.