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Sequential acquisition of chemotactic responsiveness by human spermatozoa
A Cohen-Dayag1, D Ralt, I Tur-Kaspa
1Department of Membrane Research and Biophysics, Weizmann Institute of Science, Rehovot, Israel.
Biology of Reproduction
|April 1, 1994
Summary
Human sperm are attracted to follicular fluid, but this ability changes over time. This dynamic sperm response may help select the best sperm to fertilize an egg.
Area of Science:
- Reproductive Biology
- Sperm Physiology
- Chemotaxis
Background:
- Human spermatozoa exhibit chemotaxis towards follicular fluid, showing increased motility and hyperactivation.
- Understanding the dynamics of sperm responsiveness is crucial for reproductive success.
Purpose of the Study:
- To quantify the dynamic response of human spermatozoa to chemotactic factors in follicular fluid.
- To investigate the changing identity of responsive spermatozoa within a population over time.
Main Methods:
- Exposing human spermatozoa to a gradient of a chemotactically active follicular fluid fraction.
- Separating sperm subpopulations based on their accumulation in the attractant gradient.
- Quantifying the fraction of responsive spermatozoa and monitoring changes in responsiveness over time.
Main Results:
- Only 2-12% of the total sperm population exhibited chemotactic responsiveness at any given time.
- Responsive spermatozoa gradually lost their attraction ability over time.
- Spermatozoa initially deficient in responsiveness acquired this ability as time progressed.
Conclusions:
- The identity of responsive spermatozoa is not fixed but continuously changes within the population.
- Sperm chemotaxis and enhanced motility likely function in vivo to select and deliver capacitated sperm to the egg.
- This dynamic selection mechanism may optimize the chances of fertilization upon ovulation.