RESUMO
capacitation of human sperm is essential for fertilization and is characterized visually by hyperactivated motility. There is a controversy whether reactive oxygen radicals cause infertility or stimulate sperm-zona interaction. We investigated the exact role of reactive oxygen radicals on hyperactivation (HA) of human sperm which could be a part of the capacitation process. Hyperactivation of human sperm was compared to the Ham's F-10 controls by the addition of superoxide anion and hydrogen peroxide generating enzymes on the percale treated sperms. The motility parameters of human sperms were estimated by computer assisted semen analysis system. The addition of xanthine + xanthine oxidase + catalase (generating system of superoxide anion and removal of hydrogen peroxide) on the sperms induced levels of HA (10.5% at 2 hour, 11.3% at 5 hour) which were about 2 times higher than those of controls (HA: 5.4% at 2 hour, 5.6% at 5 hour). The addition of glucose + glucose oxidase (generation of hydrogen peroxide) decreased the levels of HA (0.0% at 2 and 5 hour) significantly. Superoxide dismutase, the scavenger of superoxide anion inhibited HA significantly, whereas catalase, the scavenger of hydrogen peroxide promoted HA significantly These results suggest that the reactive oxygen radicals may be involved in hyperactivation of human sperms by the way that superoxide anion promotes and hydrogen peroxide inhibits hyperactivation of the fertile human sperms. It may be very important in the process of fertilization that promotion or inhibition of hyperactivation occurs at the proper time and location of female genital organ.