Micro-centrifugation of human spermatozoa: its effect on fertilization of hamster oocytes after micro-insemination spermatozoal transfer

Abstract

Micro-centrifugation (MC) at 6500 r.p.m. (3352 g) has not been used previously for spermatozoal concentration and subsequent fertilization. We investigated MC for micro-insemination spermatozoal transfer (MIST) of human spermatozoa from normal donors into hamster oocytes. MC resulted in reduced penetration of hamster oocytes, both after MIST [77.4% (41/53) versus 87.8% (43/49) for control; NS] and after exposure to zona-free hamster oocytes [60.8% (79/130) versus 72.7% (88/121) for control; P < 0.05]. However, MIST under the zona resulted in better incorporation of sperm nuclei when compared with zona-free hamster oocytes, for spermatozoa exposed to micro-centrifugation (77.4 versus 60.8%, P < 0.05) and controls (87.8 versus 72.7%, P < 0.05). Polyspermy was higher after MIST [22.0% (9/41) versus 13.9% (11/79); NS] for MC + , and [25.6% (11/43) versus 13.6% (12/88); NS] for MC-. We conclude that MC does have a negative, but minimal effect on the fertility of human spermatozoa with respect to hamster oocytes.