EFFECT OF SODIUM-NITROPRUSSIDE ON SPERM MOTILITY, VIABILITY, AND LIPID-PEROXIDATION

Objective: To analyze the effect of sodium nitroprusside, a nitric oxi de releaser, on sperm motion and lipid peroxidation-induced membrane d amage in cryopreserved human sperm. Design: Post-thaw, cryopreserved, human sperm samples were washed and divided into three aliquots. Each aliquot was incubated with either 0, 50, or 100 nM sodium nitroprussid e. Interventions: Samples were analyzed for lipid peroxidation (measur ed by malonaldehyde-thiobarbituric acid reactivity) at 3 hours post-th aw. Main Outcome Measures: Percent viability and motion parameters wer e assessed at 0, 10, and 30 minutes and 2, 3, 5, and 6 hours post-thaw . Results: All results represent a mean +/- SEM, n = 10. Lipid peroxid ation in samples incubated with 50 nM sodium nitroprusside (15.1 +/- 2 .1 nM malonaldehyde/10(8) sperm) or 100 nM sodium nitroprusside (13.2 +/- 2.1 nM malonaldehyde/10(8) sperm) was significantly lower than in controls (22.7 +/- 3.1 nM malonaldehyde/10(8) sperm). Percent viabilit y was significantly reduced from 0 minutes (60.6% +/- 3.5%) to 6 hours post-thaw in controls (38.0% +/- 5.1%) but not in 50 nM (46.8% +/- 10 .4%) or 100 nM (48.8% +/- 6.5%) sodium nitroprusside-treated samples. Compared with controls (18.3% +/- 3.4%), maintenance of percent motili ty at 3 hours post-thaw was significantly improved in 50 nM (24.5% +/- 2.9%) and in 100 nM (26.3% +/- 3.2%) sodium nitroprusside-treated sam ples. Straight line velocity maintenance was significantly improved in 50 nM (37.3 +/- 1.3) and in 100 nM (37.0 +/- 1) sodium nitroprusside- treated samples as compared with controls (30.5 +/- 1.7). Significant improvements in curvilinear velocity maintenance compared with control s (56.3 +/- 2.9) also were observed in 50 nM (65.9 +/- 2.1) and 100 nM (72.1 +/- 4.1) sodium nitroprusside-treated samples. Significant diff erences in the motion parameters of sodium nitroprusside-treated sampl es were maintained at 5 and 6 hours post-thaw in comparison to control s. Conclusion: These results suggest that sodium nitroprusside is bene ficial to the maintenance of post-thaw sperm motion and viability for up to 6 hours and that reduction of lipid peroxidative damage to sperm membranes may be the mechanism for these benefits.