Sathananthan A H, Szell A, Ng S C, Kausche A, Lacham-Kaplan O, Trounson A
Human Biosciences, La Trobe University, Bundoora, Vic., Australia.
Reprod Fertil Dev. 1997;9(7):703-9. doi: 10.1071/r97028.
There is debate as to whether the acrosome reaction is necessary for sperm incorporation after intra-cytoplasmic sperm injection (ICSI). Ultrastructural evidence is presented to show that the acrosome reaction could occur in the ooplasm before sperm incorporation in mature human oocytes or the acrosome could be discarded intact before sperm incorporation in immature oocytes, matured in vitro. Both germinal vesicle and growing follicular oocytes showed sperm chromatin decondensation, with discarded acrosomes close to the sites of incorporation, and were able to form male pronuclei. This is probably the first report of microfertilization of a growing oocyte with a reticulate nucleolus by ICSI. The acrosome reaction, when it occurs, is preceded by acrosome swelling and is followed by vesiculation of surface membranes exposing the inner acrosome membrane, as observed on the surface of the zona during IVF or in the perivitelline space after subzonal sperm injection. These sperm were probably capacitated at the time of ICSI. There was subtle evidence of leaching of the acrosomal matrix from intact discarded acrosomes and from partially depleted acrosomes attached to decondensing spermheads. These sperm were probably not fully capacitated at the time of ICSI. It is concluded that both the acrosome reaction and acrosome deletion are possible prerequisites to sperm incorporation after ICSI.
关于在卵胞浆内单精子注射（ICSI）后精子纳入是否需要顶体反应存在争议。本文提供的超微结构证据表明，在成熟人类卵母细胞中精子纳入之前顶体反应可能发生在卵质中，或者在体外成熟的未成熟卵母细胞中精子纳入之前顶体可能完整地被丢弃。生发泡期和生长卵泡期的卵母细胞均显示精子染色质解聚，丢弃的顶体靠近纳入位点，并且能够形成雄原核。这可能是首次关于通过ICSI对具有网状核仁的生长中卵母细胞进行微受精的报道。顶体反应发生时，先是顶体肿胀，随后是表面膜形成小泡，暴露出顶体内膜，这在体外受精时观察到的透明带表面或卵周隙内精子注射后均可看到。这些精子在ICSI时可能已获能。有细微证据表明，完整丢弃的顶体和附着在解聚精子头部的部分耗尽的顶体中有顶体基质的渗漏。这些精子在ICSI时可能未完全获能。结论是，顶体反应和顶体缺失都是ICSI后精子纳入的可能先决条件。
