MRTF-A经TLR4/TRIF通路抗心肌缺血-再灌注介导的炎症损伤

MRTF-A alleviates myocardial ischemia reperfusion injury via inhibiting TLR4/TRIF signaling pathways

目的研究转录因子MRTF-A对心肌缺血-再灌注介导的炎症损伤的影响及机制。方法30只大鼠采用随机数字表分为假手术组、模型组、MRTF-A感染组。假手术组大鼠实行开胸手术但不构建缺血-再灌注模型,模型组结扎冠状动脉30min再松开2h建立在体心肌缺血-再灌注损伤模型,MRTF-A感染组经慢病毒感染至心肌组织过表达MRTF-A后构建模型。采用生化检测评价血清心肌酶活性、TTC染色评价心肌梗死面积、HE染色测定心肌损伤程度、免疫组织化学和qPCR检测TLR4和TRIF的表达。结果与假手术组比较,心肌缺血30min后再灌注2h明显增加血清心肌酶CK-MB、LDH活性(P<0.05);心肌组织梗死面积成灰白色,梗死面积为(54.31±3.07)%(P<0.05);心肌纤维变形和紊乱,心肌细胞肿胀破裂,炎性细胞浸润明显;TRL4、TRIF的蛋白和mRNA表达明显上调(P<0.05)。与模型组对比,心肌感染MRTF-A至心肌后,CK-MB、LDH水平明显降低(P<0.05);心肌梗死面积显著减少,梗死面积为(16.74±4.26)%(P<0.05);心肌结构接近正常,轻度水肿,少量炎性细胞浸润;TRL4、TRIF的蛋白和mRNA表达显著下降(P<0.05)。结论转录因子MRTF-A在心肌细胞过表达后,通过抑制TLR4/TRIF信号通路,降低血清心肌酶活性和梗死面积,减轻心肌缺血-再灌注损伤。

Objective To observe the effect of myocardial transcription factor MRTF-A on myocardium inflammation and its mechanism.Methods Totally 30 rats were randomly divided into the sham,ischemia-reperfusion(myocardial ischemia 30 min and reperfusion 2 h),and MRTF-A groups(myocardial ischemia 30 min and reperfusion 2 h&Lentivirus infection MRTF-A)(n=10 each group).Serum myocardial enzyme activity was detected by biochemical analysis,myocardial infarct size detected by TTC,and degree of myocardial injury was measured by HE staining.The TLR4 and TRIF expression was analyzed by immunohistochemistry and qPCR.Results Compared with the sham group,the MRTF-A group significantly increased the activity of serum myocardial enzymes CK-MB and LDH(P<0.05).The infarct area of myocardial tissue was gray-white,and the infarct area was(54.31±3.07)%(P<0.05).Myocardial fibrosis was disorder,myocardial cell was swollen and burst,and inflammatory cell infiltration was obvious.Protein and mRNA expressions of TRL4 and TRIF were significantly up-regulated(P<0.05).Compared with the ischemia-reperfusion group,the levels of CK-MB and LDH were significantly reduced after myocardial infection with MRTF-A(P<0.05).The myocardial infarction area was significantly reduced to(16.74±4.26)%(P<0.05).The myocardial structure was nearly normal with mild edema.Protein and mRNA expression of TRL4 and TRIF decreased significantly(P<0.05).Conclusions The overexpression of transcription factor MRTF-A in myocardial cells alleviates the myocardial ischemia reperfusion injury by inhibiting the TLR4/TRIF signaling pathway and reducing the serum myocardial enzyme activity and myocardial damage.