肿瘤坏死因子-α诱导连接蛋白43重构在心力衰竭大鼠室性心律失常发生中的作用

Roles of tumor necrosis factor-α in regulation of Connexin43 and ventricular arrhythmias in rats with heart failure

目的观察肿瘤坏死因子-α(TNF-α)对心力衰竭大鼠连接蛋白(Cx)43表达和分布调控作用,并探讨其与室性心律失常发生的关系。方法 36只SD大鼠随机分为3组,每组12只:心衰组(F组)、加药组(D组)、假手术组(S组)。通过腹主动脉缩窄法构建心力衰竭模型,D组待术后第2周开始应用TNF-α螯合剂rhTNFR:Fc至第16周。术后第16周应用程序刺激诱发室性心律失常,记录各组诱发情况。Western blot检测心肌组织TNF-α、总CX43(T-Cx43)、磷酸化CX43(P-Cx43)和非磷酸化CX43(NP-Cx43)的蛋白表达水平,应用激光共聚焦显微镜观察T-Cx43的分布情况。结果与S组相比,F组心肌组织TNF-α表达显著增加(P<0.05),T-Cx43表达下降且分布紊乱,P-Cx43水平下降且NP-Cx43水平增加(P<0.05),室性心律失常诱发率明显升高(P<0.05);与F组比较,D组TNF-α表达显著减少(P<0.05),T-Cx43和P-Cx43水平有所增加(P<0.05),NP-Cx43水平下降(P<0.05),T-Cx43分布紊乱有所减轻,室性心律失常诱发率显著下降(P<0.05)。结论心力衰竭大鼠心肌组织中过表达的TNF-α可以诱导Cx43重构,其在心衰室性心律失常的发生中可能发挥重要作用。

This study was designed to investigate the effect of tumor necrosis factor-α（TNF-α） on expressionand distribution of Connexin43（Cx43） and ventricular arrhythmias in rats with heart failure. In this study, thirty-sixSprague-Dawley rats were randomly divided into three groups（n=12 in each group）： Heart failure group（F group）,Drug group（D group） and Sham group（S group）. The rat heart failure model was constructed by abdominal aortaligation, and rhTNFR：FC was given from 2^（nd）week to 16^（th）week after ligation in D group. Programmed electricalstimulation was imposed on the hearts of the three groups to induce ventricular arrhythmia. The expression levels ofTNF-α and total Cx43（T-Cx43）, phosphorylation CX43（P-Cx43）, and non-phosphorylation Cx43（NP-Cx43） weredetected by Western blot assay; the distribution of T-Cx43 was observed by laser scanning confocal microscope.Data showed that the protein expression level of TNF-α was higher（P〈0.05）, and the expression levels of T-Cx43 and P-Cx43 were lessened（P〈0.05）, the expression level of NP-Cx43 and the incidence of ventricular arrhythmiawere increased（P〈0.05）, and the distribution of T-Cx43 was disordered in F group, as compared S group. Inaddition, compared with F group, D group demonstrated lower protein expression level of TNF-α（P〈0.05）, higherexpression of T-Cx43 and P-Cx43, decreased level ofNP-Cx43（P〈0.05）, reversed distribution of T-Cx43,and decreased incidence of ventricular arrhythmia（P〈0.05）. In conclusion, TNF-α over expressed in myocardial tissue can induce Cx43 reconfiguration, and play an important role in ventricular arrhythmia of rats withheart failure.