Assessment of human sperm function after hydrogen peroxide exposure: development of a vaginal contraceptive

Abstract

The reactive oxygen species (ROS) that is most damaging to human spermatozoa is hydrogen peroxide. Using an artificial medium Ham’s F-10, we have evaluated the effect of different concentrations of hydrogen peroxide (H 2O 2) on various sperm function characteristics to develop a water-based vaginal contraceptive. H 2O 2 at 30 and 60 μM had no effect on sperm motility. At 120 μM of H 2O 2, a significant reduction (90–95%) in motility was observed after 120 min. However, at 600 μM of H 2O 2, all the sperm were found immotile within 15 min of incubation. At much higher concentrations (1200–1500 μM), the effect was immediate. After immobilization with H 2O 2 (600 μM in media), viability in sperm declined to 36% after 30 min, and was further reduced to 5% in 60 min. On the other hand, hypo-osmotic swelling response in these sperm went down drastically from 72 to 46% immediately after immobilization and there was no response at all after 60 min. In contrast, when Triton-x-100 (0.01%), a known spermicidal agent, was used in place of H 2O 2, the immediate loss of sperm motility corresponded simultaneously with the loss of the other two functional parameters. Further, H 2O 2 immobilized sperm revealed reduced (25–30%) nuclear chromatin decondensation as compared to 70% for the controls. A composition containing 2% H 2O 2 in 0.9% NaCl was tested in rats as a vaginal contraceptive, depicting 100% efficacy in mating studies after 2 h of vaginal application. The findings indicate the potential of developing a water-based vaginal contraceptive using H 2O 2 at an optimal concentration as utilized in the present study.