家兔急性心肌梗死后梗死周边区心交感神经受损的研究  

Research of cardiac sympathetic nerve injured in the infarcted border zone after acute myocardial infarction in rabbits

作　　者：王瑾[1] 杨波[1] 王腾[1] 

机构地区：[1]武汉大学人民医院心内科,湖北武汉430060

出　　处：《中国心脏起搏与心电生理杂志》2008年第6期539-542,共4页Chinese Journal of Cardiac Pacing and Electrophysiology

摘　　要：目的探讨家兔急性心肌梗死(简称心梗)后梗死周边区心交感神经受损对家兔心电生理的影响。方法20只家兔随机分为两组:假手术组(n=10)和心梗组(n=10)。采用结扎冠状动脉左室支的方法制备心梗模型,假手术组开胸后穿线但不结扎左室支,其他同心梗组。梗死后1 h刺激支配心脏的交感神经,观察刺激前后梗死周边区,内、中、外三层心肌单相动作电位复极90%的时程(MAPD90)的变化,并计算跨室壁复极离散度(TDR)及其变化。测定心室颤动(简称室颤)阈值。免疫组化法研究梗死周边区心肌中酪胺酸羟化酶(TH)阳性纤维的分布和密度。结果假手术组交感神经刺激后三层心肌的MAPD90较基础状态明显缩短(P<0.01),但刺激前后TDR无显著变化(P>0.05);心梗组交感神经刺激后MAPD90缩短(P<0.05),但不如假手术组显著(P<0.01),刺激前后TDR也无显著改变(P>0.05)。两组比较,心梗组刺激后TDR较假手术组增加(P<0.01),室颤阈值显著降低(P<0.05),梗死周边区神经纤维密度较假手术组显著降低(P<0.05)。结论急性心梗后梗死周边区存在心交感神经受损,使心电不稳定性增加。Objective To explore the effect of cardiac sympathetic nerve injured in the infarcted border zone on electrophysiology after acute myocardial infarction （AMI） in rabbits. Methods 20 rabbits were randomly assigned into two groups ： sham operation group （ SO group, n = 10 ） and myocardial infarction group （ MI group, n = 10 ）. Myocardial infarction model was produced in MI group by ligating the left ventricular branch of coronary artery, MAPD at repolarization 90% （ MAPD90 ） of subendocardium, midmyocardium and subepicardium, transmural dispersion of repolarization （ TDR ） and difference of TDR before and after sympathetic nerve stimulation （SNS） and ventricular fibrillation threshold （VFT） were measured 60 min after infarction in the infarcted border zone （IBZ）. The distribution and density of tyrosine hydroxylase （ TH） in IBZ were determined with immunohistochemical technique. Above operations were the same in the SO group in which LVB was not ligated. Results MAPD90 of three layers of ventricular wall shortened markedly with SNS in SO group （P 〈 0.01 ）, but TDR did not change markedly with SNS （P 〉 0.05 ） ; MAPD90 of three layers also decreased with SNS in MI group（P 〈0.05） ,but did not change so markedly as SO group（P 〈0.01 ）, and TDR did not change markedly with SNS （ P 〉 0.05 ）, either. When two groups were compared, TDR after SNS in MI group was higher than that in SO group （ P 〈 0.01 ）. VFT was lower in MI group than that of SO group（ P 〈 0.05 ）. The density of TH positive nerves in the MI group was lower than that in the SO group （ P 〈 0.05 ）. Conclusion Cardiac sympathetic fibers injuring occurs in IBZ after AMI, which might cause cardiac electrophysiology unstable. The phenomenon might be one of the mechanisms of ventricular arrhythmias during AMI.

关 键 词：电生理学 心交感神经 急性心肌梗死 室性心律失常 

分 类 号：R542.22[医药卫生—心血管疾病] R541.7[医药卫生—内科学]