不同氧气浓度对绵羊体外受精胚胎凋亡的影响

为了研究培养环境中的氧气浓度对绵羊体外受精胚胎发育的影响。比较了低氧环境(5%O2)和高氧环境(20%O2)中绵羊体外受精胚胎的发育能力和凋亡发生情况，同时利用Real-time PCR技术检测这两种氧气浓度下绵羊体外受精胚胎中凋亡相关基因Bax和Bcl-2的表达水平。结果表明：在这两种氧气浓度下发育的绵羊体外受精胚胎，细胞凋亡信号都起始于16-细胞期，且在胚胎各发育阶段发生凋亡的比率没有明显差异，但低氧环境组的囊胚发育率和囊胚细胞数都显著高于高氧环境组的（分别为45.9%、134；14.6%、106，P＜0.05），且其囊胚细胞的凋亡指数也显著低于高氧环境组（分别为0.053、0.066，P＜0.05）；PCR的研究结果表明：不论是高氧环境还是低氧环境，在绵羊体外受精胚胎的各阶段都能检测到Bax和Bcl-2的表达。而且在囊胚阶段，低氧环境下的Bcl-2基因表达量明显高于高氧环境下的。低氧环境可以抑制绵羊胚胎细胞的凋亡，更有利于绵羊胚胎的发育。

Effect of Oxygen Tension on Apoptosis of Sheep in vitro Fertilization (IVF) Embryo

To investigate the effect of 02 tension on sheep embryo development in vitro. The developmental ability and cell apoptosis of Sheep IVF （In vitro fertilization） embryo in low （5%） and high （20%） 02 tension environment were compared. The expression profiles of apoptotic related genes Bax and Bcl-2 in sheep IVF embryos were also detected by Real-time PCR. The results showed that： the apoptosis signal of the sheep IVF embryo was all commenced from the 16-cell stage under two 02 tension environment, there was no significant difference in the rate of apoptosis among respective developmental stages under two 02 tension environment, but the blastocyst development rate and cell number of blastocyst cultured in low 02 tension environment were significantly higher than those of high 02 tension environment （45.9%,134 and 14.6%,106, respectively P〈 0.05）, and the apoptosis index of blastocyst developed in low 02 tension environment was significantly lower than that of high O2 tension environment （0.053 and 0.066, respectively P〈0.05）; As assessed by Real- time PCR, Bar and Bcl-2 were expressed in sheep IVF embryo at all stages developed in low 02 tension or high 02 tension environment. The expression of Bci-2 in sheep IVF blastoeyst developed in low 02 tension environment was significantly higher than that of high 02 tension environment. Low 02 tension environment could inhibited the apoptosis of sheep IVF embryo, and should be more beneficial to the development of sheep embryo.