BACKGROUND Mammalian oocytes are activated by intracellular calcium (Ca(2+)) oscillations following gamete fusion. Recent evidence implicates a sperm-specific phospholipase C zeta, PLCζ, which is introduced into the oocyte following membrane fusion, as the responsible factor. This review summarizes the current understanding of human oocyte activation failure and describes recent discoveries linking certain cases of male infertility with defects in PLCζ expression and activity. How these latest findings may influence future diagnosis and treatment options are also discussed. METHODS Systematic literature searches were performed using PubMed, ISI-Web of Knowledge and The Cochrane Library. We also scrutinized material from the United Nations and World Health Organization databases (UNWHO) and the Human Fertilization and Embryology Authority (HFEA). RESULTS AND CONCLUSIONS Although ICSI results in average fertilization rates of 70%, complete or virtually complete fertilization failure still occurs in 1-5% of ICSI cycles. While oocyte activation failure can, in some cases, be overcome by artificial oocyte activators such as calcium ionophores, a more physiological oocyte activation agent might release Ca(2+) within the oocyte in a more efficient and controlled manner. As PLCζ is now widely considered to be the physiological agent responsible for activating mammalian oocytes, it represents both a novel diagnostic biomarker of oocyte activation capability and a possible mode of treatment for certain types of male infertility.

中文翻译：

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卵母细胞活化、磷脂酶 C zeta 和人类不育症。

背景配子融合后，哺乳动物卵母细胞被细胞内钙 (Ca(2+)) 振荡激活。最近的证据表明精子特异性磷脂酶 C zeta，PLCζ，它在膜融合后被引入卵母细胞，是负责因素。本综述总结了目前对人类卵母细胞激活失败的理解，并描述了最近将某些男性不育病例与 PLCζ 表达和活性缺陷联系起来的发现。还讨论了这些最新发现如何影响未来的诊断和治疗选择。方法 使用 PubMed、ISI-Web of Knowledge 和 Cochrane 图书馆进行系统的文献检索。我们还仔细检查了来自联合国和世界卫生组织数据库 (UNWHO) 以及人类受精和胚胎学管理局 (HFEA) 的材料。结果与结论 尽管ICSI的平均受精率为70%，但在1-5%的ICSI周期中仍会发生完全或几乎完全受精失败。虽然在某些情况下可以通过人工卵母细胞激活剂（如钙离子载体）克服卵母细胞激活失败，但更具生理性的卵母细胞激活剂可能会以更有效和受控的方式释放卵母细胞内的 Ca(2+)。由于 PLCζ 现在被广泛认为是负责激活哺乳动物卵母细胞的生理因子，它既代表了卵母细胞激活能力的新诊断生物标志物，也代表了某些类型男性不育症的可能治疗模式。1-5% 的 ICSI 周期仍会发生完全或几乎完全受精失败。虽然在某些情况下可以通过人工卵母细胞激活剂（如钙离子载体）克服卵母细胞激活失败，但更具生理性的卵母细胞激活剂可能会以更有效和受控的方式释放卵母细胞内的 Ca(2+)。由于 PLCζ 现在被广泛认为是负责激活哺乳动物卵母细胞的生理因子，它既代表了卵母细胞激活能力的新诊断生物标志物，也代表了某些类型男性不育症的可能治疗模式。1-5% 的 ICSI 周期仍会发生完全或几乎完全受精失败。虽然在某些情况下可以通过人工卵母细胞激活剂（如钙离子载体）克服卵母细胞激活失败，但更具生理性的卵母细胞激活剂可能会以更有效和受控的方式释放卵母细胞内的 Ca(2+)。由于 PLCζ 现在被广泛认为是负责激活哺乳动物卵母细胞的生理因子，它既代表了卵母细胞激活能力的新诊断生物标志物，也代表了某些类型男性不育症的可能治疗模式。