Ducibella T
Department of Obstetrics/Gynecology, Tufts University School of Medicine, Boston, MA 02111, USA.
Hum Reprod Update. 1996 Jan-Feb;2(1):29-42. doi: 10.1093/humupd/2.1.29.
Blocks to polyspermic fertilization are necessary to prevent the incorporation of two sperm nuclei into a zygote's genome, which would result in abnormal development. Many mammalian eggs utilize both an extracellular zona pellucida block to polyspermy and a plasma membrane block. Although little is known about the plasma membrane block in mammals, fertilization results in zona glycoprotein modifications caused by enzymes released by the egg and its cortical granules (CG). This article reviews other recent investigations demonstrating that the oocyte's ability to cause CG release and the block to polyspermy develops near the time of ovulation. The development of normal "activation competence' is likely to involve preovulatory changes in the oocyte's ability to signal the release of intracellular calcium as well as to respond to this calcium increase, resulting in CG exocytosis. Because normal activation competence appears to have a brief temporal window after oocyte meiotic maturation is resumed and since the oocytes are collected at various stages in assisted reproductive procedures, these studies are relevant to optimizing clinical success.
防止多精受精的屏障对于阻止两个精子细胞核融入受精卵基因组是必要的，否则会导致异常发育。许多哺乳动物的卵子利用细胞外透明带阻止多精受精和质膜阻止多精受精这两种方式。尽管对哺乳动物的质膜阻止多精受精了解甚少，但受精会导致由卵子及其皮质颗粒（CG）释放的酶引起的透明带糖蛋白修饰。本文综述了其他近期研究，这些研究表明卵母细胞引发皮质颗粒释放和阻止多精受精的能力在排卵时临近阶段发育。正常“激活能力”的发育可能涉及排卵前卵母细胞信号释放细胞内钙以及对这种钙增加做出反应的能力变化，从而导致皮质颗粒胞吐。由于正常激活能力似乎在卵母细胞减数分裂成熟恢复后有一个短暂的时间窗口，并且由于在辅助生殖程序中卵母细胞是在不同阶段收集的，所以这些研究对于优化临床成功率具有重要意义。
