抑制miR-155对心肌缺血/再灌注模型心肌细胞凋亡及炎性反应的影响

Effect of inhibiting miR-155 on apoptosis and inflammation reaction in myocardial ischemia-reperfusion model

目的探讨抑制miR-155对心肌缺血/再灌注(MI/R)模型心肌细胞凋亡及炎性反应的影响。方法以大鼠心肌细胞系H9c2为研究对象,将细胞分为4组:空白对照组、心肌缺血再灌注组(MI/R组)、阴性对照组、miR-155抑制剂组。RT-qPCR检测各组心肌细胞miR-155、NF-κB信号通路相关基因和Bax、Bcl-2 mRNA表达水平;ELISA检测IL-8、TNF-α的含量;流式细胞测量术检测心肌细胞凋亡率;Western blot检测各组细胞NF-κB信号通路相关基因和Bax、Bcl-2蛋白表达。结果与空白对照组相比,MI/R组miR-155表达水平均显著升高(P<0.05);与MI/R组相比,miR-155抑制剂组miR-155表达水平显著降低(P<0.05)。MI/R组心肌细胞凋亡率、IL-8、TNF-α的含量、Bax及NF-κB信号通路相关基因蛋白及mRNA表达水平均较空白对照组显著升高,而Bcl-2蛋白和mRNA表达水平降低(P<0.05);抑制miR-155表达后,心肌细胞凋亡率、IL-8、TNF-α的含量、Bax及NF-κB信号通路相关基因蛋白及mRNA表达水平均显著降低,而Bcl-2蛋白和mRNA表达水平升高(P<0.05)。结论抑制miR-155表达可通过降低细胞凋亡及炎性反应,从而对MI/R损伤起保护作用,其可能的作用机制是抑制NF-κB信号通路的活化。

Objective To explore the effect of inhibiting miR-155 on cardiomyocyte apoptosis and inflammation in myocardial ischemia-reperfusion(MI/R)model.Methods Myocardial cells of H9c2 rats were divided into four groups:blank control group,myocardial ischemia-reperfusion group(MI/R group),negative control group and miR-155 inhibitor group.The expressions of miR-155,NF-κB signaling pathway related genes and Bax,Bcl-2 mRNA were detected by RT-qPCR.The contents of IL-8 and TNF-αwere detected by ELISA.Western blot was used to detect the expression of NF-κB signaling pathway related genes and Bax,Bcl-2 protein.Results Compared with the control group,the expression of miR-155 in MI/R group was significantly increased(P<0.05)while the expression of miR-155 in miR-155 inhibitor group was significantly decreased(P<0.05).In MI/R group,the apoptosis rate,the content of IL-8 and TNF-α,the protein and mRNA expression of Bax and NF-κB signal pathway were significantly higher than those in the control group,while the protein and mRNA expression of Bcl-2 were lower(P<0.05).After inhibition the expression of miR-155,the apoptosis rate,the content of IL-8 and TNF-α,the protein and mRNA expression level of Bax and NF-κB signal pathway related gene were significantly decreased,while the protein and mRNA expression by Bcl-2 were increased(P<0.05).Conclusions Inhibition of miR-155 expression can protect MI/R injury through inhibition of apoptosis and inflammation.The potential mechanism is the inhibition of the activation of NF-κB signaling pathway.