胚胎移植时机对牛体细胞克隆胚胎妊娠率的影响

Effect of Implantation Time on the Pregnancy of Bovine Somatic Nuclear Transfer Embryos

以活体取卵OUP来源的牛卵母细胞为受体胞质,以Holstein奶牛的牛耳成纤维细胞作为供核细胞进行体细胞克隆,并将发育7 d的克隆囊胚和体内胚分别及体外胚进行移植,观察移植时机对受孕率的影响。依据代孕牛排卵后天数的不同分为3个实验组,组1:排卵后5～6 d(不含6 d);组2:排卵后6～7d;组3:排卵后7～8 d(不含7 d)。结果显示:对于体外胚胎而言,第2组的受孕率高于第1组(P>0.05),第3组的受孕率最低(P<0.05),且120 d的受孕率为0。与此相反,对于体内胚胎,第3组的受孕率高于其他2组。通过实验可以证明对于7 d的体外胚胎选择在代孕牛排卵后6—7 d移植可以得到较高的受孕率:而对于体内胚胎而言则应选择在受体牛排卵后7～8 d移植,可得到较高的妊娠率。

In the present study, oocytes recovered by ovum pick up （OPU） were used as recipient cytoplasm and Holstein fibroblasts as donor cells for cloning. 7-day-blastocysts from in vivo, in vitro fertility （1VF） and somatic cell nuclear transfer （SCNT）, were im- planted to the surrogates on the 5-6th day （not including the 6th day, group 1）,the 6-7th day （group 2）, and the 7-8th day （not in- cluding the 7th day, group 3） after ovulating respectively. The results showed that blastocysts derived from IVF and SCNT resulted in better pregnancy on 90 d and 120 d in group 2 than that of group 1 （P〉0.05）, arid the lowest pregnancy was observed in group 3 compared with the others （P〈0.05）, while the group 3 was found to be the best one among these groups to the in vivo blastocyst im- plantation. In conclusion, 7 day in vitro embryos should be implanted to the surrogates on the 6-7th day after ovulation while 7day in vivo embryos should be implanted to the surrogate on the 7-8th day after ovulation.