[Methodological study for human in-vitro fertilization related to maturity of gametes]

The correlations with maturity of gametes and fertilizability was studied. Specimens of semen were treated by several methods for induction of capacitation and acrosome reaction (AR). Follicular oocytes were recovered with endoscopic aspiration procedures, and divided to two groups: 1, maturing in vivo (preovulatory) and 2, immature. Immature oocytes were divided further into two subgroups: 1, germinal vesicle breakdown (GVBD) and 2, first polar body formation (FPB), after maturation culture. The sperms treated with the centrifuge-trypsinization-layering method showed a higher incidence of in-vitro fertilization (69.2%) and cleavage (51.3%) of human preovulatory eggs compared with other capacitation inducing methods. It was found that human spermatozoa that have undergone the acrosome reaction prior to zona attachment are capable of fertilizing eggs under the in vitro conditions. On the estimation of fertilizability with reference to egg maturity, 52.5% (21/40) of IMIV-GVBD and 64.7% (22/34) of IMIV-FPB eggs were fertilized. However, only 12.5% (5/40) of IMIV-GVBD and 11.8% (4/34) of IMIV-FPB eggs cleaved. These results showed that IMIV eggs had fair fertilizability, but no developmental capacity after the first cleavage. This may due to prematurity of the cytoplasm in IMIV eggs.