RESUMEN
This study was performed to determine the effects of nitric oxide on human sperm cell function. Semen samples were obtained from normal healthy volunteers. Motile spermatozoas collected by swim-up method were incubated up to 24 hours in Ham's F-10 medium supplemented with a various concentration of sodium nitroprusside (nitric oxide releasing agent). Sperm motility, hyperactivation, acrosome reaction rate, and acrosin activity were determined. The results are as follows; 1. 1mM of SNP resulted in a significant decrease in sperm motility (44.8%+/- 8.9%:78.1%+/-6.3%, and hyperactivation (10.4%+/-6.4%:477%+/-9.5%) after incubation for 3 hours compared with the control group (Ham's F-10 alone), but had no effect on acrosome reaction. 2. At 100muM SNP, sperm motility was reduced after incubation for 6 hours (54.8%+/- 3.2%) compared with that of the control group (82.7% +/- 8.9%), but hyperactivation and acrosome reaction were not affected. 3. However, a lower concentration (less than 101M) of SNP had no effect on sperm motility and hyperactivation for 8 hours of incubation but significantly decreased them when incubation periods were increased up to 24 hours compared with the control group. On the other hand, 1muM and l0muM SNP significantly increased the acrosome reaction rate in both acrosomal status (17.3%+/-5.2%,23.5%+/-4.7%, respectively) and acrosin activity (34.3muIU+/- 10.5muIU, 45.6muIU+/-5.6muIU, respectively) as compared with the control group (7.0%+/-4.0%, 9.5muIU+/-3.4muIU). These results indicate that SNP, NO releasing agent, has a dose-dependent effects on the sperm cell function. Therefore it may positively affect the fertilization by promoting acrosomal reaction at a lower concentration (less than 101M).