妊娠兔胎盘细胞凋亡及凋亡相关基因Bcl-2和Bax表达的动态变化

以新西兰雌兔为动物模型，研究妊娠期间胎盘细胞凋亡及其凋亡调控蛋白Bcl-2和Bax表达的动态变化.基因组DNA凝胶电泳实验检测到妊娠中期和晚期胎盘基因组DNA中出现典型的凋亡特征——DNA梯带，而且DNA断裂值在妊娠早、中、晚期分别为：0.14、0.49和1.43，与妊娠早期相比，妊娠中、晚期胎盘基因组DNA断裂值有显著性增加.TUNEL实验和活化caspase-3的免疫定位实验表明，在妊娠早期胎盘中存在细胞凋亡，而且在各妊娠期中细胞凋亡主要发生于合体滋养层.免疫印迹法分析表明，Bcl-2和Bax随妊娠的进行其表达量明显增加，Bax∶Bcl-2比值在妊娠早、中、晚期分别为：0.89，0.91和1.25，呈增加趋势.实验结果说明，在兔正常妊娠中，胎盘合体滋养层细胞发生凋亡，且随妊娠的进行，凋亡细胞数量增多，胎盘细胞凋亡主要与细胞中Bax∶Bcl-2的比例相关.

Change of Apoptosis and Apoptotic Relative Gene Bcl-2 and Bax Expression in Pregnant Rabbit Placenta

The change of apoptosis and apoptotic regulatory gene Bcl-2 and Bax expression in pregnant rabbit placenta were investigated. Nuclear DNA fragmentation analysis indicated that DNA ladder, which is characteristic of apoptosis was detected in D18 and D26 pregnant rabbit placenta and the scan results showed that DNA fragmentation increased significantly in D18 and D26 pregnant rabbit placenta compared with that in D12 pregnant rabbit placenta. TUNEL test and immunolocalization of active caspase-3 demonstrated that apoptosis occurred in D12 pregnant rabbit placenta, and apoptotic cells localized predominantly in syncytiotrophoblast throughout pregnancy. Immunoblot analysis showed an increase of Bcl-2 and Bax expression throughout pregnancy, and the change of expression of these two proteins resulted in an increase in Bax to Bcl-2 ratio. The results demonstrated that apoptosis occurred in syncytiotrophoblast in rabbit pregnancy and apoptotic cell death increased from early to the end of gestation period, moreover Bax to Bcl-2 ratio may be related to apoptosis in placenta.