抄録
Sperm-zona pellucida (ZP) binding is the initial step in fertilization. In this study, to examine sperm-ZP binding properties, we collected ZPs from oocytes obtained from gilt ovaries after 0, 20, 44, and 68 h of maturation culture, and counted the number of sperm bound to the ZP (NSBZ) after 2 min of sperm-ZP co-incubation. Culture of cumulus oocyte complexes (COCs) for 44 h produced significantly higher NSBZ than the other culture durations. Culture of denuded oocytes (DO) produced the same result. To examine the effect of cumulus cells (CCs) and the maturity of oocytes on the NSBZ after maturation culture for 44 h, three oocyte culture conditions (COCs, DO, and combination of DO and CCs) were established, and oocytes were categorized according to the presence of a polar body (PB). The NSBZ did not differ among the culture conditions. NSBZ of oocytes with a PB was greater than that of oocytes without a PB. The addition of tunicamycin, a potent inhibitor of N-linked glycosylation, to the COC maturation medium significantly decreased the NSBZ, although the maturation rate was not affected. In conclusion, NSBZ increases during oocyte maturation and oocytes play a key role in increasing the NSBZ via modification of N-linked glycosylation.
