Dozortsev D, De Sutter P, Rybouchkin A, Dhont M
Department of Gynaecology and Obstetrics, University Hospital of Gent, Belgium.
Hum Reprod. 1995 Nov;10(11):3012-7. doi: 10.1093/oxfordjournals.humrep.a135838.
We investigated the time course of human oocyte activation after intracytoplasmic sperm injection (ICSI) by observing the oocyte chromosome configuration at different times after injection. One day old human oocytes were injected with spermatozoa and subjected to cytogenetic analysis at 2, 3, 4 and 5 h after injection. We found that anaphase is initiated in the vast majority of the oocytes between 2 and 3 h after injection, and that by 4-5 h after injection most of the oocytes have reached the chromatin mass stage. Two distinguishable stages of sperm nucleus transformation were observed. The first phase-swelling-was reached within 2 h after the injection and was independent of oocyte activation. The second phase-the "brush'-like stage or decondensed chromatin stage-was found only in activated oocytes. Moreover, this stage was not reached before the chromatin mass stage (late telophase) of the oocyte. The same proportion of metaphase II oocyte chromosome configurations and unchanged sperm nuclei was found at any given time after injection. We conclude that: (i) ICSI allows users to obtain an almost synchronized population of activated oocytes; (ii) anaphase II is initiated in the majority of oocytes not later than 2-3 h after injection and telophase II is reached approximately 5 h after injection; and (iii) there are two distinguishable phases of sperm nucleus transformation after ICSI: oocyte activation-independent swelling of the sperm head and oocyte activation-dependent chromatin decondensation which is coupled to the beginning of oocyte chromosome decondensation.
我们通过观察胞浆内单精子注射（ICSI）后不同时间的卵母细胞染色体构型，研究了人类卵母细胞激活的时间进程。将一天龄的人类卵母细胞注射精子，并在注射后2、3、4和5小时进行细胞遗传学分析。我们发现，绝大多数卵母细胞在注射后2至3小时开始进入后期，并且在注射后4至5小时，大多数卵母细胞已达到染色质团阶段。观察到精子核转化有两个可区分的阶段。第一阶段——肿胀——在注射后2小时内达到，且与卵母细胞激活无关。第二阶段——“刷状”阶段或染色质解聚阶段——仅在激活的卵母细胞中发现。此外，在卵母细胞的染色质团阶段（末期晚期）之前未达到该阶段。在注射后的任何给定时间，中期II卵母细胞染色体构型和未变化的精子核的比例相同。我们得出以下结论：（i）ICSI使使用者能够获得几乎同步的激活卵母细胞群体；（ii）大多数卵母细胞在注射后不迟于2至3小时开始进入后期II，末期II大约在注射后5小时达到；（iii）ICSI后精子核转化有两个可区分的阶段：与卵母细胞激活无关的精子头部肿胀和与卵母细胞染色体解聚开始相关的依赖于卵母细胞激活的染色质解聚。
