Superoxide dismutase content in sperm correlates with motility recovery after thawing of cryopreserved human spermatozoa.

Objective: To investigate the correlation between sperm superoxide dismutase (SOD) content and motility recovery after thawing of cryopreserved human sperm, based on the rationale that this antioxidant enzyme provides protection against reactive oxygen species-induced damage during cryopreservation.

Design: Prospective study.

Setting: Private infertility institute and university-based research laboratory.

High cholesterol content and decreased membrane fluidity in human spermatozoa are associated with protein tyrosine phosphorylation and functional deficiencies.

Poor-quality sperm show reduced capacity to undergo capacitation-induced protein tyrosine phosphorylation and hyperactivation. Given that these deficiencies can be overcome by membrane-permeant stimulators of the cAMP-dependent kinase system, we hypothesize that the main defect underlying these deficiencies resides on the sperm plasma membrane. Spermatozoa from semen samples obtained from 15 consenting healthy donors were separated in 2 subpopulations, L45 (first interface) and L90 (pellet), using a 45:65:90 ISolate gradient centrifugation method.

Effect of thawing temperature on the motility recovery of cryopreserved human spermatozoa.

Objective: To investigate the effects of thawing temperature on sperm function after cryopreservation. The technical aspects of sperm cryopreservation have significantly improved over the last few decades. However, a standard protocol designed to optimize sperm motility recovery after thawing has not yet been established.

Capacitation-associated changes in membrane fluidity in asthenozoospermic human spermatozoa.

The fertilizing potential of human spermatozoa relies on their ability to capacitate as they travel through the female reproductive tract. During this process, cholesterol is released from the plasma membrane, altering its architecture and dynamics. Using ISolate gradients, we obtained high (L90)- and low (L45)-quality spermatozoa from asthenozoospermic human semen samples.

Decreased protein tyrosine phosphorylation and membrane fluidity in spermatozoa from infertile men with varicocele.

Varicocele is a prevalent pathology among infertile men. The mechanisms linking this condition to infertility, however, are poorly understood. Our previous work showed a relationship between sperm functional quality and the ability of spermatozoa to respond to capacitating conditions with increased membrane fluidity and protein tyrosine phosphorylation.