VandeVoort C A, Yudin A I, Overstreet J W
California Regional Primate Research Center, Department of Obstetrics and Gynecology, School of Medicine, University of California, Davis 95616, USA.
Biol Reprod. 1997 May;56(5):1307-16. doi: 10.1095/biolreprod56.5.1307.
In this study we investigated the ultrastructure of macaque sperm induced to acrosome-react with calcium ionophore A23187, and the interaction between these acrosome-reacted sperm and the macaque zona pellucida. Transmission electron microscopy revealed that the majority of ionophore-treated sperm retained the vesiculated acrosomal cap or "shroud." Untreated, acrosome-reacted sperm on the zona had a similar ultrastructural appearance. In sperm-zona binding experiments, a mean of 4.5 ionophore-treated sperm were bound per zona after 1 min of coincubation compared with 41 sperm per zona in the solvent control. Vigorous pipetting was used to remove the acrosomal shrouds from approximately 50% of acrosome-reacted sperm before incubation with oocytes. Significantly more of these mechanically treated sperm were bound to the zona after a 4-min coincubation compared with acrosome-reacted sperm that were not pipetted. The number of mechanically treated sperm bound to the zona was the same whether the sperm and oocytes were coincubated in calcium-free medium or in control medium. The percentage of mechanically treated sperm that were acrosome-reacted on the zona also was not different in the two media. We conclude that macaque sperm that undergo the acrosome reaction on the zona surface are bound by the acrosomal shroud before zona penetration. When sperm acrosome-react before interaction with the oocyte, their zona binding capacity is significantly reduced. Removal of the acrosomal shroud and exposure of the inner acrosomal membrane increases the affinity of sperm for the zona. This sequence occurs naturally during the transition from primary binding to secondary binding on the zona surface.
在本研究中，我们调查了经钙离子载体A23187诱导发生顶体反应的猕猴精子的超微结构，以及这些发生顶体反应的精子与猕猴透明带之间的相互作用。透射电子显微镜显示，大多数经离子载体处理的精子保留了囊泡状的顶体帽或“罩”。未处理的、在透明带上发生顶体反应的精子具有相似的超微结构外观。在精子-透明带结合实验中，共孵育1分钟后，每个透明带上平均有4.5个经离子载体处理的精子结合，而溶剂对照组中每个透明带上有41个精子。在与卵母细胞孵育前，用强力吹吸法去除了约50%发生顶体反应的精子的顶体罩。与未进行吹吸处理的发生顶体反应的精子相比，在共孵育4分钟后，这些经机械处理的精子与透明带结合的数量明显更多。无论精子和卵母细胞是在无钙培养基中还是在对照培养基中共孵育，经机械处理的精子与透明带结合的数量都是相同的。在两种培养基中，在透明带上发生顶体反应的经机械处理的精子的百分比也没有差异。我们得出结论，在透明带表面发生顶体反应的猕猴精子在穿透透明带之前被顶体罩所束缚。当精子在与卵母细胞相互作用之前发生顶体反应时，它们与透明带的结合能力会显著降低。去除顶体罩并暴露顶体内膜会增加精子对透明带的亲和力。这一序列在从透明带表面的初级结合到次级结合的转变过程中自然发生。
