Ang Ⅱ对左心室心肌跨室壁复极不均一性的影响  

Effects of Ang Ⅱ on transmural dispersion of ventricular repolarization in left ventricular myocardium

作　　者：钟江华[1] 何喜民[2] 陈小盼[2] 左琦[2] 林云[2] 黄珊[2] 吴平生[1] 

机构地区：[1]南方医科大学附属南方医院心内科,广东广州440100 [2]海南医学院附属医院心内科,海南海口570102

出　　处：《中国现代医学杂志》2013年第5期31-34,共4页China Journal of Modern Medicine

基　　金：海口市重点科技计划项目(No:2012-077)

摘　　要：目的观察AngⅡ灌流对家兔左心室心肌跨室壁复极不均一性及Cx43蛋白分布异质性的影响,探讨AngⅡ在恶性室性心律失常(MVA)发生中的作用。方法将20只家兔随机分成正常对照组和AngⅡ灌流组,正常对照组离体心脏给予单纯改良台氏液灌流,AngⅡ灌流组则给予含1μmol AngⅡ的台氏液灌流,分别检测两组家兔的室颤阈值(VFT)及心外膜下、中层心肌和心内膜下心肌细胞的单相动作电位复极90%时程(APD90)、跨室壁复极离散度(TDR)以及三层心肌Cx43蛋白表达的差异。结果①正常对照组和AngⅡ灌流组的VFT分别为(13.40±2.950)V和(8.30±1.77)V,两组对比差异有统计学意义(P<0.001)。②与正常对照组比较,AngⅡ灌流组三层心肌的APD90均明显延长(P<0.05)。AngⅡ灌流组和正常对照组的ΔAPD90分别为(34.70±9.68)ms和(23.70±5.68)ms,TDR分别为(49.30±13.52)ms和(36.10±12.44)ms,AngⅡ灌流组均明显大于正常对照组(P<0.05),说明AngⅡ灌流组中层心肌APD90的延长较心外膜下和心内膜下心肌更为明显。③与正常对照组比较,AngⅡ灌流组三层心肌的Cx43蛋白表达均有明显下降(P<0.05),但以中层心肌的下降最为显著。结论 AngⅡ灌流改变了正常家兔左心室心肌的跨室壁Cx43表达异质性,使左心室心肌跨室壁复极不均一性增大,VFT下降,更加容易诱发MVA。【Objectives】 To observe the effects of Ang Ⅱ on transmural heterogeneity of ventricular repolarization in left ventricular myocardium of rabbit,and explore the role of Ang Ⅱ on malignant ventricular arrhythmia（MVA）.【Methods】 20 rabbits were randomly divided into control group and Ang Ⅱ group.Isolated hearts were simply perfused with modified Tyrode＇s solution in the control group,and with Tyrode＇s solution containing 1 μM Ang Ⅱ in the Ang Ⅱ group.Ventricular fibrillation threshold（VFT）,90% monophasic action potential repolarization duration（APD90） of subepicardial,midmyocardial and subendocardial myocardium,transmural dispersion of repolarization（TDR） and Cx43 protein expression in three layers of myocardium were measured in both groups.【Results】 VFT in the control group and the Ang Ⅱ group were（13.40 ± 2.95） V,and（7.20 ± 1.69） V respectively.There was a significant difference between two groups（P 0.001）.APD90 of three myocardial layers in the Ang Ⅱ group were significantly prolonged more than those in the control group（P 0.01）.ΔAPD90 in the Ang Ⅱ group and the control group were（34.70 ± 9.68） ms and（23.70 ± 5.68） ms,and TDR were（49.30 ± 13.52） ms and（36.10 ± 12.44） ms respectively.ΔAPD90 and TDR in the Ang Ⅱ group were significantly higher than those in the control group（P 0.05）,which showed that APD90 of midmyocardium extended more obviously in the Ang Ⅱ group.Cx43 protein expression of all three myocardial layers were decreased obviously in the Ang Ⅱ group（P 0.05）,but reduction was more significant in the midmyocardium（P 0.001）.【Conclusion】 Ang Ⅱ can increase transmural heterogeneity of Cx43 expression and repolarization in left ventricular myocardium of rabbit,and decrease VFT and made it more easily induce MVA.

关 键 词：AngⅡ 缝隙连接 复极不均一 中层心肌 

分 类 号：R541.7[医药卫生—心血管疾病]