沉默信息调节因子1对缺氧心肌细胞凋亡和自噬的影响

Effects of Silencing Sirt1 on Apoptosis and Autophagy of Hypoxic Cardiomyocytes

目的:分析沉默信息调节因子1(Sirt1)对缺氧条件下心肌细胞凋亡和自噬的影响。方法:将心肌H9c2细胞分为Control组、Hypoxia组(缺氧处理24h)、NC+Hypoxia组(转染阴性对照并缺氧处理24h)和Sirt1+Hypoxia组(转染Sirt1过表达载体并缺氧处理24h)。以qRT-PCR和Western blot测定心肌细胞中Sirt1 mRNA和蛋白表达水平,MTT方法评估细胞存活率,流式细胞术测定细胞总凋亡水平,Western blot检测凋亡蛋白Bax、Cleaved Caspase-3水平和自噬蛋白LC3-Ⅱ/Ⅰ、Beclin-1水平。结果:与Control组比较,Hypoxia组细胞中Sirt1 mRNA和蛋白表达水平降低,细胞存活率降低,细胞凋亡率和Bax、Cleaved Caspase-3蛋白水平升高,LC3-Ⅱ/Ⅰ、Beclin-1蛋白水平降低(P<0.05)。与NC+Hypoxia组比较,Sirt1+Hypoxia组细胞中Sirt1 mRNA和蛋白表达水平升高,细胞存活率升高,细胞凋亡率和Bax、Cleaved Caspase-3蛋白水平降低,LC3-Ⅱ/Ⅰ、Beclin-1蛋白水平升高(P<0.05)。结论:Sirt1可抑制缺氧心肌细胞凋亡并诱导细胞自噬。

Objective:To study the effects of Sirt1 on autophagy and apoptosis in cardiomyocytes under hypoxia.Method:Myocardial H9c2 cells were divided into four groups:Control,Hypoxia,NC+Hypoxia,Sirt1+Hypoxia(transfected Sirt1 overexpression vector and hypoxic treatment).The effects of hypoxia on Sirt1 expression and overexpression in myocardial cells were measured by qRT-PCR and Western blot.MTT method was used to evaluate cell viability.Annexin V-FITC/PI method was used to determine the total apoptosis level of cells.The levels of apoptotic protein Bax,Cleaved Caspase-3 and autophagic protein LC3-II/I and Beclin-1 were detected by Western blot.Results:Compared with Control group,the expression level of Sirt1 in Hypoxia group was decreased,cell activity was decreased,the apoptosis rate and the level of Bax and Cleaved Caspase-3 protein were increased,the level of LC3-II/I and Beclin-1 were decreased.Compared with NC+Hypoxia group,the expression of Sirt1 in Sirt1+hypoxia group was increased,cell activity was increased,the apoptosis rate and the level of Bax and Cleaved Caspase-3 protein were decreased,LC3-II/I and Beclin-1 levels were increased.Conclusion:Sirt1 inhibits cardiomyocyte apoptosis and induces autophagy with hypoxia.