Gook D, Osborn S M, Bourne H, Edgar D H, Speirs A L
Reproductive Biology Unit, Royal Women's Hospital, Carlton, Victoria, Australia.
Mol Hum Reprod. 1998 Dec;4(12):1130-5. doi: 10.1093/molehr/4.12.1130.
In this study we examined 138 oocytes which were meiotically mature and, on light microscopic examination, contained either no or one pronucleus following intracytoplasmic sperm injection (ICSI). Oocytes were fixed and simultaneously stained for chromatin (Hoechst 33258) and the spindle (alpha-tubulin antibody). In nine oocytes, no sperm nucleus was observed. The remaining oocytes were separated into two groups following staining; (i) oocytes which had remained at metaphase II after ICSI (n = 74); and (ii) oocytes in which resumption of meiosis was observed after ICSI (n = 55). In all oocytes in which sperm chromatin was absent no resumption of meiosis had occurred and therefore parthenogenetic activation by the process of ICSI seems to be a rare event. In 17 out of 74 (23%) oocytes which remained at metaphase II, staining identified premature chromosome condensation (PCC) of the sperm chromatin (G1-PCC). Sperm nuclear decondensation or further transformation of the sperm chromatin was observed in 56 out of 74 (76%) oocytes which remained at metaphase II after ICSI and in 46 out of 55 (84%) oocytes which had resumed meiosis, indicating that initiation of sperm decondensation is independent of the resumption of meiosis in the oocyte. In contrast, transition of the sperm nucleus beyond the decondensed stage only occurred in association with resumption of meiosis in the oocyte (no pronuclei in metaphase II oocytes). The presence of both male and female pronuclei in 53% of oocytes which had resumed meiosis indicates that changes in sperm chromatin beyond the initial decondensation stage are dependent on cytoplasmic conditions which also permit female pronuclear formation.
在本研究中，我们检查了138个减数分裂成熟的卵母细胞，经光学显微镜检查，这些卵母细胞在胞浆内单精子注射（ICSI）后含有无原核或一个原核。将卵母细胞固定，同时用染色质（Hoechst 33258）和纺锤体（α-微管蛋白抗体）进行染色。在9个卵母细胞中未观察到精核。其余卵母细胞在染色后分为两组；（i）ICSI后停留在减数分裂中期II的卵母细胞（n = 74）；（ii）ICSI后观察到减数分裂恢复的卵母细胞（n = 55）。在所有无精子染色质的卵母细胞中，均未发生减数分裂恢复，因此ICSI过程导致的孤雌激活似乎是罕见事件。在74个停留在减数分裂中期II的卵母细胞中，有17个（23%）经染色鉴定出精子染色质出现早熟染色体凝聚（PCC）（G1-PCC）。在ICSI后停留在减数分裂中期II的74个卵母细胞中的56个（76%）以及减数分裂已恢复的55个卵母细胞中的46个（84%）中观察到精子核解聚或精子染色质的进一步转化，这表明精子解聚的起始与卵母细胞减数分裂的恢复无关。相反，精子核超出解聚阶段的转变仅在卵母细胞减数分裂恢复时发生（减数分裂中期II的卵母细胞中无原核）。在减数分裂已恢复的卵母细胞中，53%存在雄原核和雌原核，这表明精子染色质在初始解聚阶段之后的变化取决于也允许雌原核形成的细胞质条件。
