EFFECTS OF ANTIOXIDANTS ON HUMAN SPERM PREPARATION TECHNIQUES

The effect of two different sperm preparation techniques, Percoll grad ient centrifugation and swim-up from a washed pellet were tested on th e functional competence of the selected spermatozoa. Percoll gradient centrifugation brought about an improvement in sperm motility paramete rs such as curvilinear velocity and straight-line velocity, an increas e in the rates of hyperactivation and the acrosome reaction and an inc rease in the percentage of motile spermatozoa. after 24 h of incubatio n compared to the centrifugation, swim-up procedure. The effects of an tioxidants such as dithiothreitol (DTT) or reduced glutathione (GSH), and reactive oxygen species-scavenging enzymes such as catalase or sup eroxide dismutase (SOD) during the stage of centrifugation before the swim-up procedure were also studied. Though all of these agents preven ted the fall in sperm motility after 24 h incubation, only DTT and SOD improved the rates of both hyperactivation and the acrosome reaction. GSH also improved the acrosome reaction, whereas catalase was without significant effect on the rates of hyperactivation or the acrosome re action. These results indicate that Percoll gradient centrifugation se lects spermatozoa with better functional competence than does centrifu gation swim-up. The damage caused by the centrifugation can be prevent ed by the addition of antioxidants, suggesting that the differences no ted with the Percoll gradient method was due to better protection agai nst peroxidative damage due to the centrifugation of unselected sperma tozoa. However, the use of DTT is limited by virtue of the fact that t his sulphydryl reducing agent leads to destabilization of the sperm ch romatin. In contrast, GSH and SOD could have therapeutic potential.