ALK4对心肌梗死后心肌纤维化的影响和作用机制  

Effect and mechanism of ALK4 on myocardial fibrosis after myocardial infarction

作　　者：陈一和[1] 林慧[2] 逯朝阳 相银 刘俊[1] CHEN Yihe;LIN Hui;LU Zhaoyang;XIANG Yin;LIU Jun(Department of Cardiology,the First Affiliated Hospital of Wenzhou Medical University,Wenzhou 325000,China;Department of Respiratory Medicine,the Second Affiliated Hospital of Wenzhou Medical University,Wenzhou 325000,China)

机构地区：[1]温州医科大学附属第一医院心内科,浙江温州325000 [2]温州医科大学附属第二医院呼吸科,浙江温州325000

出　　处：《中国现代医生》2018年第36期29-33,共5页China Modern Doctor

基　　金：浙江省自然科学基金资助项目(LQ17H020005)

摘　　要：目的研究ALK4在心梗后心肌纤维化中的作用及分子机制。方法利用ALK4^(+/-)小鼠和野生型C57BL/6小鼠构建心梗模型,通过天狼星红染色检测纤维化,用WB、Real-time PCR、免疫组化技术检测梗死边缘区α-SMA、collagen1a-1、CTGF的表达,探讨ALK4在心梗后心肌纤维化中的作用。分离及培养原代ALK4^(+/-)小鼠心脏成纤维细胞,在低氧刺激下(1%O2)研究ALK4对心脏成纤维细胞增殖、分化和分泌合成功能的影响。结果心梗后第28天,梗死边缘区ALK4蛋白表达水平升高,ALK4敲除后则显著少其表达。与野生型同窝对照小鼠(WT)相比,ALK4^(+/-)小鼠梗死后生存率提高[ALK+/-(77.1)%vs WT(54.3)%,P<0.05],心脏功能改善[LVEF:ALK+/-(48.5±3.5)%vs WT (29.3±3.8)%,P<0.05;FS:ALK+/-(24.5±2.2)%vs WT (13.9±1.9)%,P<0.05],梗死边缘区心肌纤维化减少[ALK+/-(32.1±2.0)%vs WT(22.5±2.2)%,P<0.05]。细胞实验中,ALK4敲除则显著抑制低氧刺激下心脏成纤维细胞增殖[ALK4^(+/-)(2.68±0.23) vs W(1.86±0.42),P<0.05]、分化[ALK4^(+/-)(2.72±0.21) vs WT(1.43±0.31),P<0.05]和分泌合成[ALK4^(+/-)(9.87±0.74) vs WT(4.13±1.31),P<0.05]。ALK4^(+/-)敲除抑制低氧下Smad3的磷酸化水平[ALK4^(+/-)(1.64±0.17) vs WT(2.79±0.32),P<0.05]而不影响Smad4表达量。结论 ALK4表达抑制可显著抑制心梗后心肌纤维化,改善心室功能和生存率以及钝化心脏成纤维细胞对低氧刺激的反应,其作用主要通过抑制Smad3/4信号通路。Objective To study the role and molecular mechanism of ALK4 in myocardial fibrosis after myocardial infarction.Methods The MIK4^+/-mice and wild-type C57BL/6 mice were used to construct the myocardial infarction model.Fibrosis was detected by Sirius red staining.WB,Real-time PCR and immunohistochemical techniques were used to detect the expression ofα-SMA,collagen1a-1 and CTGF in the infarct edge zone.The role of ALK4 in myocardial fibrosis after myocardial infarction was explored.Primary ALK4^+/-mouse cardiac fibroblasts were isolated and cultured,and the effects of ALK4 on proliferation,differentiation and secretion of cardiac fibroblasts were studied under hypoxia(1%O2).Results On the 28th day after myocardial infarction,the expression level of ALK4 protein in the infarct border area was increased,and the expression was significantly less after ALK4 knockout.Compared with that of the wild-type littermate control mice(WT),the post-infarction survival rate(ALK^+/-(77.1)%vs.WT(54.3)%,P<0.05)and cardiac function(LVEF:ALK^+/-(48.5±3.5)%vs WT(29.3±3.8)%,P<0.05;FS:ALK^+/-(24.5±2.2)%vs WT(13.9±1.9)%,P<0.05)was improved,and myocardial fibrosis was reduced in the infarct border zone(ALK^+/-(32.1±2.0)%vs WT(22.5±2.2)%,P<0.05)in ALK4^+/-mice.In cell experiments,ALK4 knockout significantly inhibited cardiac fibroblast proliferation under hypoxic stimulation(ALK4^+/-(2.68±0.23)vs WT(1.86±0.42),P<0.05),differentiation(ALK4^+/-(2.72±0.21)vs WT(1.43±0.31),P<0.05)and secretory synthesis(ALK4^+/-(9.87±0.74)vs WT(4.13±1.31),P<0.05).ALK4^+/-knockdown inhibited the phosphorylation of Smad3 under hypoxia(ALK4^+/-(1.64±0.17)vs WT(2.79±0.32),P<0.05)without affecting the amount of Smad4 expression.Conclusion The inhibition of ALK4 expression can significantly inhibit myocardial fibrosis after myocardial infarction,improve ventricular function and survival rate,and inactivate the response of cardiac fibroblasts to hypoxia stimulation,mainly through inhibition of Smad3/4 signaling pathway.

关 键 词：ALK4 心肌梗死 心肌纤维化 心脏成纤维细胞 

分 类 号：R285[医药卫生—中药学]