不同高浓度CO_2对2-细胞小鼠胚胎体外发育的影响

Effect of Different High CO_2 Concentrations on the Development of 2-cell Mouse Embryos in vitro

目的 :观察不同高浓度二氧化碳 ( CO2 )对 2 -细胞小鼠胚胎体外发育的影响。方法 :获取小鼠 2 -细胞胚胎 ,置于 CZB培养液微滴 ,覆盖经三蒸水处理的石蜡油 ,分别在 5 % CO2 (对照组 )、5 .7%CO2 、6.0 % CO2 和 1 5 % CO2 浓度下体外培养 ;在 1 5 % CO2 时 ,另设覆盖经磷酸盐缓冲液 ( PBS)处理的石蜡油或不覆盖石蜡油的实验组 ,观察胚胎发育情况。结果 :5个实验组的囊胚率均显著低于对照组 ( P<0 .0 1 ) ,5 .7% CO2 时仅为 4.3% ,其余 4组的均为 0。 CO2 浓度 5 .7%和 6.0 %时 ,胚胎大部分停滞在 2 -细胞和 4-细胞期 ,两者间无统计学差异 ( P>0 .0 5 )。CO2 浓度 1 5 %时 ,覆盖经三蒸水处理的石蜡油组 ,有 1 5 %的胚胎发育到 4-细胞阶段 ,但 4-细胞胚胎的卵裂球不规则 ,很快退化 ;覆盖经 PBS处理过的石蜡油组 ,有 2 .2 %的胚胎发育到 4-细胞 ,其余出现严重的退化。结论 :高浓度 CO2 对小鼠胚胎发育有强毒性效应 ,引致胚胎发育停滞和严重降解 ;高浓度 CO2 时 ,胚胎覆盖三蒸水处理石蜡油的效果优于经 PBS处理的石蜡油 ;严密监控 CO2

Objective: To investigate the effect of different high CO 2 concentrations on the development of 2 cell mouse embryos in vitro . Methods: At the CO 2 levels of 5% (control group), 5.7%, 6.0% and 15%, embryos were incubated in drops with CZB medium, and the drops were covered by paraffin oil which was treated with three distilled water. In addition, at the CO 2 level of 15%, there were another two groups, in which paraffin oil was treated with phosphate buffered saline (PBS) or the drops were uncovered. The development of embryos in all stages was recorded. Results: The developmental rates of blastocysts in five experimental groups were significantly lower than that of the control group ( P <0.01). At the CO 2 level of 5.7% , the developmental rate of blastocysts was 4.3%, and those of other experimental groups were 0. At the CO 2 levels of 5.7% and 6.0%, embryos were blocked in the 2 cell or 4 cell stage, and no significant difference was showed between the two groups ( P >0.05). At the CO 2 level of 15%, 15% embryos developed in the 4 cell stage with irregular blastomere and degenerated quickly in the group whose paraffin oil was treated with distilled water; 2.2% embryos developed in the 4 cell stage in the group which paraffin oil was treated with PBS and the rest stagnated in the 2 cell stage. Conclusion: The high CO 2 concentration had toxic effect on the development of 2 cell mouse embryos in vitro , and was responsible for the inhibition of the embryos. At the CO 2 level of 15%, the embryos in the group whose paraffin oil was treated with three distilled water developed better than one whose paraffin oil was treated with PBS. It is important for the development of embryos in vitro to strictly monitor CO 2 concentration.