主动脉弓缩窄诱导大鼠心肌肥大Raf/MEK/ERK通路的变化  

The regulatory mechanism of Raf/MEK/ERK pathway on the rat cardiac hypertrophy induced by transverse aortic constriction

作　　者：富丹婷 屠珏[1] 蔡月琴[1] 蔡兆伟[1] 张利棕[1] 刘景艳 徐山春 王德军[1] FU Dan-ting;TU Jue;CAI Yue-qin;CAI Zhao-wei;ZHANG Li-zong;LIU Jing-yan;XU Shan-chun;WANG De-jun(Laboratory Animal Research Center/Institute of Comparative Medicine Zhejiang Chinese Medical University,Hangzhou 310053;Department of Internal Medicine,the First Affiliated Hospitial of Zhejiang Chinese Medicine University,Hangzhou 310006,China)

机构地区：[1]浙江中医药大学动物实验研究中心/比较医学研究所,杭州310053 [2]浙江中医药大学附属一院中内科,杭州310006

出　　处：《中国应用生理学杂志》2020年第1期33-39,共7页Chinese Journal of Applied Physiology

基　　金：浙江中医药大学科研基金项目(国家自然科学基金预研专项,2018ZG35);浙江省中医药优秀青年人才基金项目(2020ZQ017)。

摘　　要：目的:通过观察心肌肥大大鼠加速纤维肉瘤/丝裂素活化蛋白激酶激酶/胞外信号调节蛋白激酶(Raf/MEK/ERK)通路关键因子的基因和蛋白表达及蛋白磷酸化修饰水平上的变化,了解Raf/MEK/ERK通路在心肌肥大调控中的作用。方法:20只SD大鼠随机分为假手术组和模型组,通过主动脉弓缩窄(TAC)法建立心肌肥大模型,12周后颌下静脉取血分离血清,检测氨基末端脑钠肽前体(NT-proBNP)含量,之后进行超声心动图测定和麻醉下的血流动力学测定,收集心肌标本,观察心肌组织的病理学改变,检测心肌组织Raf/MEK/ERK通路的关键因子基因、蛋白表达水平及蛋白磷酸化水平的变化。结果:与假手术组比较,TAC模型组大鼠超声心动图的左室舒张末期室间隔厚度(IVSd)、左室收缩末期室间隔厚度(IVSs)、左室后壁舒张末期厚度(LVPWd)、左室后壁收缩末期厚度(LVPWs)显著增厚(P<0.05,P<0.01),左室收缩末期内径(LVIDs)显著减小(P<0.01),左心室质量(LV Mass)、左心系数LW(LV Mass/Weight)比值显著增加(P<0.05,P<0.01);大鼠心率(HR)、左心室最大收缩速率(+dp/dtmax)、左心室最大舒张速率(-dp/dtmax)均显著降低(P<0.01),血清中NT-pro BNP含量显著增加(P<0.01);心肌细胞排列杂乱,心肌细胞肥大、胞质明显增多,炎症细胞浸润,出现大量胶原纤维沉积,大面积心肌细胞呈现蓝色;大鼠心肌组织中c-Raf在Ser259和Ser338上的磷酸化蛋白phospho-c-Raf(Ser259)和phospho-c-Raf(Ser338)表达水平显著升高(P<0.01),其下游MEK1/2、ERK1/2的磷酸化蛋白phospho-MEK1/2(Ser217/Ser221)和phospho-ERK1/2(Thr202/Tyr204)表达水平也显著增高(P<0.01)。结论:Raf/MEK/ERK通路在心肌肥大中的调控作用,可能通过激活关键因子c-Raf、MEK1、MEK2、ERK1和ERK2特异性位点的磷酸化实现的。Objective:To investigate the mRNA,protein expression levels and the phosphorylation levels of key factors in rapidly accelerated fibrosarcoma/mitogen-activated protein kinase kinase/extracellular regulated protein kinases(Raf/MEK/ERK)pathway,and to clarify the regulatory function of Raf/MEK/ERK pathway in myocardial hypertrophy.Methods:Twenty SD rats were divided into sham-operated group and model group.The myocardial hypertrophy model was established by transverse aortic constriction(TAC).At 12 weeks after TAC,blood samples were collected from the submandibular vein,and the serum was separated to detect the content of N terminal pro B type natriuretic peptide(NT-proBNP).After that,the rats were subjected to echocardiography and hemodynamic measurement.Then the pathological changes of myocardial tissue were observed.And the levels of mRNA,protein expression and the phosphorylation of key factors in Raf/MEK/ERK pathway were detected in myocardial tissue.Results:Compared with sham-operated group,left ventricular end-diastolic interventricular septal thickness(IVSd),left ventricular end-systolic interventricular septal thickness(IVSs),left ventricular end-diastolic posterior wall thickness(LVPWd)and left vebtricular end-systolic posterior wall thickness(LVPWs)in TAC model group were increased significantly(P<0.05,P<0.01),left ventricular end-systolic diameter(LVIDs)was decreased significantly(P<0.01),LV Mass and LW(LV Mass/Weight)were increased significantly(P<0.05,P<0.01).The levels of heart rate(HR),left ventricular pressure maximal rate of rise(+dp/dtmax),left ventricular pressure maximal rate of fall(-dp/dtmax)were decreased significantly(P<0.01).The serum level of NT-proBNP in TAC rat was increased significantly(P<0.01).The myocardial cells in TAC model group were arranged disorderly,myocardial cell hypertrophy,cytoplasm were increased significantly,and inflammatory cells infiltrated.A large amount of collagen fibers were deposited and large area of myocardial cells were stained blue in TAC rat.The expression l

关 键 词：大鼠 Raf/MEK/ERK通路 心肌肥大 主动脉弓缩窄 调控机制 

分 类 号：R33[医药卫生—人体生理学]