【摘要】 目的:通过建立拟交感性心房颤动(房颤)模型,探讨心肌缝隙连接蛋白(Cx)43和Cx40表达水平的变化。方法:选择杂种犬15只,随机分为3组,即:对照组(N组)、快速心房起搏组(RAP组)和快速心房起搏+异丙肾上腺素(ISO)灌流组(RAP+ISO组),每组5只,处死后取出心脏,建立langendorff心脏离体灌流模型。3组分别检测心房有效不应期(AERP)及房颤诱发率,免疫组化检测神经生长因子、酪氨酸羟化酶在细胞内的表达及分布,蛋白免疫印记法检测Cx43和Cx40总蛋白水平,透射电镜检测线粒体形态,荧光比色法检测线粒体内活性氧簇(ROS)生成量。结果:与N组AERP[(166±5.1)ms]比较,RAP组AERP[(160±3.2)ms]无明显改变,无法诱发出房颤,RAP+ISO组AERP[(148±3.7)ms]明显缩短(P<0.05),并可成功诱发房颤。与N组比较,RAP组线粒体轻度肿胀,基质基本完整,RAP+ISO组线粒体明显肿胀,部分基质透明。RAP组和RAP+ISO组Cx43和Cx40总蛋白含量均低于N组(P<0.05),且RAP+ISO组蛋白含量低于RAP组(P<0.05)。RAP+ISO组神经生长因子、酪氨酸羟化酶分布和含量以及线粒体内ROS生成量显著高于RAP组和N组(P<0.05),而RAP组则高于N组(P<0.05),差异均有统计学意义。结论:交感性房颤的发生与Cx43和Cx40蛋白含量的变化有关,交感神经可能通过氧化应激下调Cx43和Cx40的蛋白含量来介导房颤的发生。更多还原

【Abstract】 Objective: To explore the expression of myocardial levels of connexin 43(Cx43), Cx40 in experimental dog model of sympathomimetic atrial fibrillation(AF). Methods: 15 mongrels dogs were randomly divided into 3 groups: Control group, Rapid atrium pacing(RAP) group and RAP+isoprenaline(ISO) perfusion group. n =5 in each group. The hearts were taken to establish in vitro langendorff cardiac perfusion model. Atrial effective refractory period(AERP) and AF inducing rate were tested; intracellular expression and distribution of nerve growth factor(NGF) and tyrosine hydroxylase(TH) were examined by immunohistochemistry, total protein contents of Cx43 and Cx40 were measured by Western blot analysis, mitochondria morphology was observed by transmission electron microscope and mitochondria reactive oxygen species(ROS) generation was detected by fluorescent colorimetric method. Results: AERP was similar between Control group and RAP group(166±5.1) ms vs(160±3.2) ms which cannot induce AF; while it was shortened in RAP+ISO group(148±3.7) ms, P <0.05 which may successfully induce AF.Compared with Control group, mitochondria was slightly swollen in RAP group and the matrix was intact, while mitochondria was obviously swollen in RAP+ISO group and part of matrix was transparent; total protein contents of Cx43 and Cx40 were lower in both RAP group and RAP+ISO group, P <0.05; in addition, they were even lower in RAP+ISO group than RAP group, P <0.05. Compared with Control group and RAP group, RAP+ISO group had increased expression and distribution of NGF, TH and mitochondria ROS generation, P <0.05; NGF, TH and ROS in RAP group were higher than Control group, P <0.05. Conclusion: Sympathetic AF has been related to the contents and changes of myocardial levels of CX43 and Cx40; sympathetic nerve might trigger AF by oxidative stress induced down-regulation of myocardial CX43 and Cx40 in experimental dog model.更多还原