Taniguchi T, Taniguchi R, Kanagawa H
Department of Theriogenology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
J Vet Med Sci. 1996 Jul;58(7):635-40. doi: 10.1292/jvms.58.635.
The present study was conducted to investigate the influence of aging of recipient oocyte on the developmental ability of reconstituted mouse embryos produced from the cytoplast of oocytes and single blastomeres of early or late 2-cell stage embryos by electrofusion. Oocytes were obtained at 14 (newly ovulated oocytes), 18, 22 (oocyte that time passed after ovulation; aged oocyte) hr after hCG injection and oocyte cytoplast was produced by manual enucleation using a fine glass needle under the dissecting microscope. The aging of the oocytes significantly influenced on the fusion rate of the reconstituted embryos (14 hr: 42.7-47.2% vs. 22 hr: 75.3-77.6%). Similarly, the cleavage rate of reconstituted embryos increased with aging of the oocytes (14 hr: 50.8-56.3% vs. 22 hr: 82.2-90.7%). The percentage of reconstituted embryos produced from cytoplast of aged oocytes (22 hr post hCG) and single blastomeres of late 2-cell stage embryos developing to the blastocyst (20.8%) was significantly higher than that of reconstituted embryos produced by other combinations (2.0-8.2%: P < 0.01). Although cell cycle stage of donor nuclei influenced to developmental ability of reconstituted embryos, these results are probably related to the aging of the oocytes since aged oocytes can be activated more easily by electrical stimulation than newly ovulated oocytes.
本研究旨在探讨受体卵母细胞老化对通过电融合由卵母细胞胞质体与2-细胞期早期或晚期胚胎的单个卵裂球构建的重构小鼠胚胎发育能力的影响。在注射hCG后14小时（新排卵的卵母细胞）、18小时、22小时（排卵后经过一定时间的卵母细胞；老化卵母细胞）获取卵母细胞，并在解剖显微镜下使用精细玻璃针通过手动去核产生卵母细胞胞质体。卵母细胞的老化对重构胚胎的融合率有显著影响（14小时：42.7 - 47.2% 对比 22小时：75.3 - 77.6%）。同样，重构胚胎的卵裂率随着卵母细胞的老化而增加（14小时：50.8 - 56.3% 对比 22小时：82.2 - 90.7%）。由老化卵母细胞（hCG注射后22小时）的胞质体与2-细胞期晚期胚胎的单个卵裂球构建的重构胚胎发育至囊胚的比例（20.8%）显著高于其他组合构建的重构胚胎（2.0 - 8.2%：P < 0.01）。尽管供体细胞核的细胞周期阶段会影响重构胚胎的发育能力，但这些结果可能与卵母细胞的老化有关，因为老化卵母细胞比新排卵的卵母细胞更容易被电刺激激活。
