Wang Z J, Trounson A, Dziadek M
Centre for Early Human Development, Monash Medical Centre, Clayton, Vic., Australia.
Reprod Fertil Dev. 1990;2(6):683-91. doi: 10.1071/rd9900683.
Mouse embryos were mechanically bisected at the morula, early blastocyst or expanded blastocyst stages of development and cultured in vitro to the expanded blastocyst stage. Their capacity for postimplantation development was assessed after transfer to pseudopregnant foster mice. Embryos bisected at blastocyst stages had a higher survival rate in vitro than those bisected at the morula stage. Half-embryos had approximately half the number of cells at the blastocyst stage as control embryos, but the proportion of cells in the inner cell mass (ICM) was unaltered. The implantation rate of blastocysts derived from bisected embryos was only slightly lower than that of control embryos, but bisected embryos had a significantly reduced capacity to form fetuses. Histological analyses showed that failure to form a fetus is due to the absence of egg cylinder development, which correlates with the reduced number of cells in the ICM of bisected embryos. Postimplantation viability of half-embryos was significantly higher when blastocysts were transferred to Day-3 rather than Day-4 pseudopregnant recipients, presumably because of an increase in cell number in vivo prior to implantation.
将小鼠胚胎在桑椹胚、早期囊胚或扩张囊胚发育阶段进行机械分割，并在体外培养至扩张囊胚阶段。将其移植到假孕代孕小鼠后，评估它们的着床后发育能力。在囊胚阶段分割的胚胎在体外的存活率高于在桑椹胚阶段分割的胚胎。半胚胎在囊胚阶段的细胞数量约为对照胚胎的一半，但内细胞团（ICM）中的细胞比例未改变。来自分割胚胎的囊胚的着床率仅略低于对照胚胎，但分割胚胎形成胎儿的能力显著降低。组织学分析表明，未能形成胎儿是由于缺乏卵圆柱发育，这与分割胚胎ICM中细胞数量减少有关。当囊胚移植到第3天而非第4天的假孕受体时，半胚胎的着床后存活率显著更高，这可能是因为着床前体内细胞数量增加。
