PC12细胞缺氧培养后DNA损伤和修复相关基因表达的研究

目的:探讨PC12细胞缺氧后细胞凋亡与DNA损伤和修复的关系,进一步阐明缺氧导致PC12细胞凋亡的机制。方法:采用TUNEL法,结合应用流式细胞术观察PC12细胞缺氧培养不同时间点细胞凋亡现象,以及DNA损伤修复相关基因表达的改变。结果:在缺氧0.5h时,开始出现凋亡细胞,此时P53、P21waf1/cip1蛋白表达也开始增高,GADD45蛋白表达达到高峰(P<0.01)。至缺氧1h凋亡细胞达高峰,此时P53、P21蛋白表达最高(P<0.05),而GADD45表达则明显下降(P<0.05)。至缺氧6—12h,则以坏死为主,此时以上的基因表达均减弱。结论:PC12细胞缺氧早期(0.5—1h),主要出现凋亡为主的细胞死亡,伴随着DNA损伤相关基因表达的动态改变,提示缺氧后PC12细胞凋亡部分是由于DNA损伤严重,损伤不能及时修复所致。

A study on the expression of DNA damage and repair related genes after hypoxia in PC12 cell

Objective:To investigate the relationship between apoptosis and DNA damage after hypoxia in PC12 cell.Method:The apoptosis of PC12 cell in different time points after hypoxia was determined by TUNEL techniques,and the expression DNA damage related genes was observed by flow cytometry techniques.Result:Apoptotic cells appeared at 30min after hypoxia and the expression of protein P53,P21waf1/cip1,GADD45 began to increase.Apoptosis cell came to a head and the expression of protein P53,P21,GADD45 arrived the top at 1 hour following hypoxia(P<0.05). At 6hour and 12h after hypoxia,PC12 cells were mainly necrostic and expression of the genes also decresed.Conclusion:In the early period after hypoxia of PC12 cell(0.5-2h),cell death mostly are apoptosis companied with the increased expressions of DNA damage related genes.Therefore apoptosis of PC12cell after hypoxia partly is caused by serious DNA damage which cannot be repaired.