Liu Guohui, Kato Yoko, Tsunoda Yukio
Laboratory of Animal Reproduction, College of Agriculture, Kinki University, Nakamachi, Nara, Japan.
J Reprod Dev. 2007 Aug;53(4):785-90. doi: 10.1262/jrd.18121. Epub 2007 Mar 28.
Parthenogenetic activation is an important factor in successful production of cloned mammals. Because it has been reported that aged oocytes are more sensitive to parthenogenetic activation than young oocytes, the present study examined the effects of oocyte aging on the in vitro and in vivo developmental potential of nuclear-transferred (NT) mouse oocytes receiving cumulus cells. The potentials of young NT oocytes (14 h after human chorionic gonadotrophin [hCG] injection) to develop into blastocysts was, however, significantly higher than that of aged oocytes (20 h after hCG injection; 16% vs 6%). When the nuclei of NT oocytes at the 2-cell stage were fused with enucleated fertilized 2-cell embryos, the potentials of the serial NT embryos to develop into blastocysts were no different for both young and aged oocytes (74% vs 74%). Live young, however, were obtained only after transfer of serial NT blastocysts developed from young NT oocytes (2%). In contrast to a report using embryonic nuclei as the nuclear donors, the results of the present study indicate that young oocytes are superior to aged oocytes as a source of recipient cytoplasm for mouse somatic cell cloning.
孤雌激活是成功生产克隆哺乳动物的一个重要因素。由于有报道称老化卵母细胞比年轻卵母细胞对孤雌激活更敏感，因此本研究检测了卵母细胞老化对接受卵丘细胞的核移植（NT）小鼠卵母细胞体外和体内发育潜能的影响。然而，年轻的NT卵母细胞（人绒毛膜促性腺激素[hCG]注射后14小时）发育成囊胚的潜能显著高于老化卵母细胞（hCG注射后20小时；分别为16%和6%）。当2细胞期NT卵母细胞的细胞核与去核的受精2细胞胚胎融合时，年轻和老化卵母细胞的连续NT胚胎发育成囊胚的潜能没有差异（分别为74%和74%）。然而，仅在移植由年轻NT卵母细胞发育而来的连续NT囊胚后获得了活体幼崽（2%）。与使用胚胎细胞核作为核供体的报道相反，本研究结果表明，作为小鼠体细胞克隆的受体细胞质来源，年轻卵母细胞优于老化卵母细胞。
