糖尿病兔心肌梗死后心脏自主神经的变化及其与室性心律失常的关系

Changes of Autonomic Nerves and Its Effects on Inducible Ventricular Arrhythmias in Diabetic Rabbits After Myocardial Infarction

目的探讨糖尿病合并心肌梗死后兔心脏自主神经的变化及其与室性心律失常的关系。方法选择新西兰兔作为研究对象,通过高脂高糖喂养2月后由耳缘静脉注射四氧嘧啶(80mg/kg)制作糖尿病模型,并随机分为糖尿病+心肌梗死组、糖尿病假手术组和非糖尿病假手术组,通过结扎冠状动脉前降支制作心肌梗死模型。手术后所有入选成活兔均常规喂养8周,随之行活体电生理检查诱发心律失常,并采用免疫组织化学法观察心脏交感神经的形态、分布及密度变化。结果糖尿病+心肌梗死组兔室性心律失常诱发率显著高于糖尿病假手术组(P<0.05);糖尿病+心肌梗死组梗死灶周及非梗死左心室游离壁酪氨酸羟化酶阳性神经纤维密度显著高于糖尿病假手术组(P<0.05),且神经纤维分布较为紊乱。结论糖尿病兔心肌梗死后在自主神经损害的基础上出现了交感神经增生和异常再生即自主神经重构,从而使心肌梗死后室性心律失常的易感性增加。

Aim To investigate the characteristic of cardiac nerve and its influence of ventricular arrhythmias in diabetic rabbit after myocardial infarction. Methods New Zealand rabbits were fed with high-fat/high-sucrose diet in the first two months and then injected with alloxan （ 80 mg/kg of body weight） via the marginal ear vein to make diabetes mellitus; All alive rabbits were randomly divided into three groups the diabeties and myocardial infarction group, the diabeties group and the control group. Left anterior descending branch was ligated to induce myocardial infarction model. After electrophysiological recordings, immunostaining was applied to detect the shape and density of ventricular nerve fibers. Resets In the diabeties and myocardial infarction group, ventricular arrhythmias were increased compared with those in the diabeties group （ 85.7% vs 50%, P 〈 0.05 ）. The densities of TH positive nerve fibers were significantly higher in the diabeties and myocardial infarction group than in the diabeties group （P 〈 0.05 ） , and the distribution in the diabeties and myocardial infarction group was more chaotic. Conclusions There were cardiac neural remolding in diabetic rabbit＇ heart after myocardial infarction and partly associated with the post MI ventricular arrhythmias.