过表达SIRT1基因通过PI3K/AKT信号通路抑制高糖刺激心肌H9c2细胞凋亡和活性氧水平

目的:探讨过表达沉默信息调节因子1(SIRT1)对高糖刺激心肌H9c2细胞凋亡和活性氧簇(ROS)水平的影响。方法:分别用空载质粒(pcDNA3.1-NC)和SIRT1过表达质粒(pcDNA3.1-SIRT1)转染心肌细胞,并进行高糖诱导。实验分为对照组、高糖组、高糖+pcDNA3.1-NC组和高糖+pcDNA3.1-SIRT1组,用qPCR和Western blot法分别检测各组心肌H9c2细胞的SIRT1表达,噻唑蓝(MTT)法检测细胞的活力,流式细胞术检测细胞凋亡,DCFH-DA检测细胞内ROS水平,Western blot检测细胞中磷脂酰肌醇3-激酶(PI3K)、磷酸化PI3K、AKT和磷酸化AKT的蛋白水平。结果:与对照组相比,高糖诱导的心肌H9c2细胞中SIRT1表达显著降低,细胞活力显著下降,ROS水平和细胞凋亡率增加,PI3K和AKT磷酸化蛋白水平下调(P<0.05);过表达SIRT1可诱导高糖刺激的心肌H9c2细胞活力增加,ROS水平和凋亡率降低,PI3K和AKT磷酸化蛋白水平上调(P<0.05)。结论:过表达SIRT1可通过调控PI3K/AKT信号通路逆转高糖刺激心肌H9c2细胞活力的降低及凋亡率和氧化应激的增加。

Over-expression of SIRT1 gene inhibits high glucose-stimulated H9c2 cardiomyocyte apoptosis and ROS level through PI3K/AKT signaling pathway

AIM:To investigate the effects of silent information regulator 1(SIRT1)over-expression on the apoptosis and the level of reactive oxygen species(ROS)in high glucose-induced H9c2 cardiomyocytes.METHODS:H9c2 cardiomyocytes were transfected with empty plasmid(pcDNA3.1-NC)and SIRT1 over-expression plasmid(pcDNA3.1-SIRT1),and then stimulated by high glucose.The H9c2 cells were divided into control group,high glucose group,high glucose+pcDNA3.1-NC group and high glucose+pcDNA3.1-SIRT1 group.The expression of SIRT1 at mRNA and protein levels in each group was determined by qPCR and Western blot.The viability of the cells was measured by MTT assay.The apoptotic rate was analyzed by flow cytometry.The protein levels of phosphatidylinositol 3-kinase(PI3K),phosphorylated PI3K,AKT and phosphorylated AKT were examined by Western blot.RESULTS:SIRT1 was significantly decreased in high glucose-induced H9c2 cardiomyocytes,the cell viability was significantly decreased compared with control group,while the ROS levels and apoptotic rate were increased,and the phosphorylated PI3K and AKT protein levels were down-regulated(P<0.05).Over-expression of SIRT1 significantly promoted the viability of H9c2 cardiomyocytes induced by high glucose,decreased the ROS levels and apoptotic rate,and up-regulated phosphorylated PI3K and AKT protein levels(P<0.05).CONCLUSION:SIRT1 over-expression reverses the decrease in the viability of high glucose-stimulated H9c2 cardiomyocytes,and the increases in apoptotic rate and oxidative stress by regulating PI3K/AKT signaling pathway.