脯氨酰异构酶1 沉默抑制缺氧/ 复氧H9c2 心肌细胞凋亡

目的:肽基脯氨酰顺反异构酶1(Pin1)在心血管疾病发病过程中发挥重要作用,本研究检测RNA 干扰沉默Pin1 对缺氧/ 复氧诱导的大鼠胚胎心肌细胞H9c2 凋亡的影响及机制。方法:体外培养大鼠H9c2 细胞,建立缺氧/ 复氧损伤模型,模拟体内缺血再灌注损伤;RT-qPCR 和Western blot 法检测Pin1 的表达;将细胞分为空白对照组、缺氧/ 复氧组、缺氧/ 复氧组+转染Pin1 siRNA 组、缺氧/ 复氧组+转染scramble siRNA 组;MTT 法测H9c2 细胞存活率;用流式细胞术Annexin V/ PI 双染法检测细胞凋亡率;用Western blot 法检测H9c2 细胞Bax 和Bcl-2 蛋白表达;生化法检测Caspase-3 的活性水平。结果:Pin1 在缺氧/ 复氧H9c2 细胞中呈现高表达;转染Pin1 siRNA 后,Pin1 的mRNA 和蛋白表达水平均显著降低(P<0.05);与缺氧/ 复氧组比较,Pin1 siRNA 组的细胞存活率增加,凋亡率降低,Bcl-2 蛋白表达升高,Bax 蛋白表达降低,Bcl-2/ Bax 升高,Caspase-3 活性降低,差异均有统计学意义(P<0.05)。结论:Pin1 下调可减少缺氧/ 复氧诱导的心肌细胞凋亡,可能是通过上调Bcl-2,下调Bax 蛋白表达,降低Caspase-3 活性而发挥作用。

Inhibitory effects of Pin1 silencing by siRNA on apoptosis of H9c2 cardiomyo-cytes induced by hypoxia / reoxygenation

Objective:Pin1 plays an important role in the pathogenesis of cardiovascular disease,our study aims to investigate the effects of Pin1 silencing by siRNA on H9c2 apoptosis induced by hypoxia/ reoxygenation.Methods:H9c2 cells were cultured and subjected to a hypoxia/ reoxygenation (H/ R) condition in vitro,mimicking ischemic/ reperfusion injury in vivo.The mRNA and protein expression of Pin1 were detected by RT-qPCR and Western blot.H9c2 cells were divided into control group,H/ R group,H/ R+Pin1 siRNA group,H/ R+scramble siRNA group.MTT and flow cytometry with Annexin V-FITC/ PI staining were respectively performed to detect cell viability and apoptosis.The expression of Bax and Bcl-2 were measured by Western blot.The activity of Caspase-3 was detected by automatic biochemistry analytic instrument.Results:The mRNA and protein levels of Pin1 were highly expressed in the cells of H/ R group.Transfection with Pin1 siRNA strikingly inhibited the expression of Pin1.Compared with H/ R group,Pin1 siRNA markedly increased cell viability,decreased the cell apoptosis and the Caspase-3 activity.Furthermore,the increased Bcl-2,decreased Bax and the ratio of Bcl-2 to Bax were observed in Pin1 siRNA group ( P < 0.05) compared with H/ R group.Conclusion:Downregulation of Pin1 protects hypoxia/ reoxygenation-injured H9c2 cells from apoptosis,which is possibly through the upregulation of Bcl-2 and downregulation of Bax and Caspase-3 activity。