The measurement of hyaluronidase activity in human spermatozoa by substrate slide assay and its clinical application.

Acrosomal hyaluronidase activity of individual sperm can be detected by a halo formation around the sperm head on hyaluronic acid substrate slides. The following results were obtained by this method in clinical practice. A significant correlation was found between hyaluronidase activity and sperm concentration in male infertility. Hyaluronidase activity increased as the concentration of sperm increased, and the least hyaluronidase activity was determined at less than 10 X 10(6)/ml. The group with more than 40% motility had a higher hyaluronidase activity than other groups with poor motility. Although there was no significant correlation between hyaluronidase and cumulus dispersion and fertilization rates in immature oocytes, there was an excellent correlation in mature oocytes in human in vitro fertilization. These findings suggest that a newly developed assay will be useful for evaluating sperm fertilizing capacity.