Effect of nitric oxide on human sperm capacitation and acrosome reaction

Objective:To explore the effect of NO on human sperm capacitation and acrosome reaction (AR). Methods: Different concentrations of sodium nitroprusside (SNP) were added into the sperm suspension from 48 healthy and fertile men, then the suspension were incubated in 1×Earle's for 1 hour at 37℃. After progesterone induced AR for 15, 30, 45 and 60 min, ACP activity in the suspension before and after capacitation, and at different time point of AR was measured. In the meantime, sperm motile parameters were assayed by CASA. Results: ACP activity and sperm motile parameters were enhanced when NO concentration was 50 to 100 nmol/L ,they were of no significant varies in 150 to 200 nmol/L, and were descended in 250 to 300 nmol/L. Conclusion:NO have double function on sperm capacitation and AR. Sperm capacitation, AR and sperm motile parameters were facilitated in low concentration of NO and were suppressed in high concentration. ACP activity assay of sperm is an objective and reliable method to evaluate sperm capacitation and AR in whole sperm population.