Capacitation-associated changes in membrane fluidity in asthenozoospermic human spermatozoa
Mariano G Buffone1, Gustavo F Doncel, Juan C Calamera
1Laboratorio de Estudios en Reproducción (LER), Buenos Aires, Argentina.
International Journal of Andrology
|April 11, 2008
Summary
Low-motility sperm struggle to increase membrane fluidity during capacitation, impacting their fertilizing ability. This defect in sperm plasma membrane rheology is linked to poor sperm movement and function.
Area of Science:
- Reproductive Biology
- Sperm Physiology
- Membrane Biophysics
Background:
- Sperm capacitation is crucial for fertilization, involving plasma membrane changes.
- Asthenozoospermic (low motility) sperm have reduced fertilizing potential.
- Cholesterol release alters sperm membrane architecture during capacitation.
Purpose of the Study:
- To investigate if reduced fertilizing ability in asthenozoospermic sperm is due to impaired membrane fluidity changes during capacitation.
- To compare membrane fluidity and hydration in high (L90) and low (L45) quality asthenozoospermic sperm versus normozoospermic sperm.
Main Methods:
- Utilized ISolate gradients to isolate sperm populations.
- Employed fluorescent probes (DPH, TMA-DPH, PA-DPH, Laurdan) to assess membrane fluidity and hydration.
- Analyzed sperm membrane properties before and after capacitation.
Main Results:
- Asthenozoospermic sperm showed lower membrane hydration than normozoospermic sperm.
- Both L45 and L90 asthenozoospermic sperm failed to increase membrane fluidity post-capacitation, unlike normozoospermic sperm.
- Lower membrane hydration correlated with poorer sperm motion parameters.
Conclusions:
- Low-motility human spermatozoa exhibit a defect in achieving necessary membrane fluidity changes during capacitation.
- Impaired sperm plasma membrane rheology contributes to poor functional quality and reduced fertilizing ability in asthenozoospermic individuals.
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