Omi/HtrA2信号通路介导高氧诱导肺泡上皮细胞凋亡的作用及机制

摘要

Objective To explore the role and the mechanism of Omi/HtrA2 mediated apoptosis of alveolar epithelial cells induced by hyperoxia. Methods A549 cells were cultured in vitro and divided randomly into the control group,the hyperoxi-a group and the Ucf-101 group. The hyperoxia group was exposed to a mixture of O2(900ml/L)and CO2(50ml/L)for 10 minutes, then cultured in a closed environment. The Ucf-101 group was given to specific Omi/HtrA2 inhibitor Ucf-101 10μmol/L for 20 mi-nutes before hyperoxia induction. Cells were collected in 48h after culture. The morphology changes of A549 cells were observed under an inverted microscope. The apoptosis were detected by flow cytometry. The expression of Omi/HtrA2, Caspase-3 and XIAP in cytoplast of A549 cells were determined by immunohistochemistry. Results In control group, A549 cells growth in good condi-tion, were sticked to each other tightly. The suspension cells were less. Compared with the control group,the hyperoxia group have a large number of suspension cells. The gap between cells were increased. The expression of Omi/HtrA2、caspase-3 increased,and the expression of XIAP decreased. The apoptosis increased obviously(P<0. 05). Compared with the hyperoxia group,the Ucf-101 group have a decreasd number of suspension cells. The expression of caspase-3 and the apoptosis of A549 cells were significantly decreased(P<0. 05)and the expression of XIAP was increased(P<0. 05)in the Ucf-101 group. Conclusion Omi/HtrA2 may play an important role in the apoptosis of alveolar epithelial cells induced by hyperoxia. The apoptosis of alveolar epithelial cells in-duced by hyperoxia. Inhibiting the expression of Omi/HtrA2 may reduce the damage of alveolar epithelial cells.%目的：研究Omi/HtrA2在高氧诱导肺泡上皮细胞凋亡中的作用及其机制。方法以人A549细胞为研究对象,待其达到对数生长期时,随机将细胞分为对照组、高氧组和Ucf-101组。对照组仍置于5%CO 2培养箱中,高氧组即通入3L/min的90%氧气和5%二氧化碳高纯混合气10min。 Ucf-101组则为加入Omi/HtrA2的特异性阻断剂Ucf-101(终浓度为10μmol/L)预处理20min后再用高氧诱导处理。三组细胞密闭培养48h后,通过倒置相差显微镜下观察A549细胞形态学变化,流式细胞仪检测细胞凋亡率,免疫组化法检测细胞内Omi/HtrA2,Caspase-3及XIAP蛋白表达情况。结果对照组细胞呈梭形,贴壁好,细胞间隙较小,悬浮细胞少。高氧组细胞呈圆形或椭圆形,细胞间隙增宽,悬浮细胞较多,而胞浆Omi/HtrA2、caspase-3表达增多,XIAP表达明显减少,细胞凋亡率增加(P<0．05)。与高氧组相比,Ucf-101组细胞大部分呈梭形,贴壁较好,悬浮细胞减少；胞浆caspase-3表达降低,XIAP表达明显增多( P<0．05),细胞凋亡率减少( P<0．05),但未恢复至对照组水平。结论 Omi/HtrA2可能参与了高氧诱导的肺泡上皮细胞凋亡过程。通过抑制 Omi/HtrA2的活性可减轻高氧诱导的肺泡上皮细胞的损伤。