AGING, HYALURONIDASE REMOVAL OF THE CUMULUS, AND MICROINJECTION DO NOT AFFECT THE SPERM BINDING POTENTIAL OF HUMAN OOCYTES

Purpose: We studied the influence of aging, hyaluronidase removal of t he cumulus, and microinjection on the sperm binding potential of human oocytes under intact zona assay conditions to determine the safe use of unstored aged unfertilized ICSI oocytes on zona binding tests. Resu lts were also compared with those for aged IVF oocytes under the same conditions. Methods: To avoid the large variation in sperm binding sco res, we compared the ratios of the number of sperm bound to nontreated versus to treated oocytes. Treated oocytes were those whose zonae wer e exposed to hyaluronidase, an agent that decreases sperm binding. Exp erimental groups were fresh oocytes, experimentally aged fresh oocytes , fresh oocytes whose cumulus was removed either mechanically or with hyaluronidase, aged ICSI oocytes, and aged IVF oocytes. Results: Stati stical analysis within and between groups showed that aging, previous insemination, cumulus removal by hyaluronidase, and microinjection did not affect the sperm binding potential of human oocytes. Conclusions: As the zona binding ability of fresh and unfertilized aged ICSI oocyt es is similar they can be used safely in zona assays.