影响兔胚胎细胞核移植效率的因素

 对兔胚胎细胞核移植（NT）的有关影响因素进行了系统研究。结果发现电场强度100 V·mm-1，脉冲时间15μs，电脉冲3～4次的融合率显著高于其它组（P<0.05）；融合前激活卵母细胞，分裂率和囊胚率显著高于融合后激活（P <0.05）；当用8～16-细胞胚胎的卵裂球作供核时，卵裂率和囊胚率显著高于致密桑椹胚卵裂球为供核组；当重组胚在含3%发情牛血清（OCS）的TCM199中培养48 h后，转入含10% FCS的TCM199中继续培养，卵裂率和囊胚率显著高于一直在3% OCS或10% 胎犊血清（FCS）中培养的重组胚（P < 0.05）。将22枚2～4-细胞期重组胚移入同期发情的受体母兔输卵管内，34 d后产下NT仔兔1只。结果表明，电融合参数和供体胚胎的发育阶段以及受体卵母细胞的状态对NT效果有显著影响，在NT胚胎的不同发育阶段采用不同的血清种类和浓度可提高其胚胎发育能力。

Studies on the Nuclear Transfer of Rabbit

Factors affecting the efficiency of nuclear transfer (NT) in rabbits were examined in the present study. When 100 V·mm-1 of pulse strength and 15μs of pulse duration were employed, 3 and 4 electronic pulses resulted in significantly more cytoplasts fused with donor cells compared with 2 electronic pulses (P<0.05), but no significant difference was found in the cleavage rate of reconstructed embryos among the three groups (P>0.05). When the duration and number of electronic pulse were fixed at 15μs and 3 times, increase of pulse intensity from 100 V·mm-1 to 150 V·mm-1 and 200 V·mm-1 resulted in a significantly decrease in the cleavage rate of reconstructed embryos (P<0.05), although the fusion rate did not significantly differ among the three groups (P>0.05). Significantly more reconstructed embryos cleaved and developed to blastocysts when they were derived from donor embryos at the 8-16-cell stage, in comparison with the reconstructed embryos derived from donor embryos at the compact morulae stage (P<0.05), although the fusion rate was similar (P>0.05). Activation of cytoplasts prior to fusion increased the cleavage rate (P<0.05) and blastocyst development (P<0.05) of reconstructed embryos, but decreased the fusion rate (P<0.05) compared with cytoplasts activated post fusion. More reconstructed embryos developed to blastocysts when they were cultured in TCM＋3%OCS at the first 48 h and then cultured in TCM199＋10% FCS, in comparison with the reconstructed embryos cultured in either TCM199＋10%FCS or TCM199＋3%OCS (P<0.05). When 22 NT embryos were transferred into the oviducts of one recipient rabbit, one rabbit was delivered to birth. In conclusion, either electrofusion parameter or developmental stage of donor embryos have a significant effect on the efficiency of NT, NT embryos require different concentration of serum at their different development stages.