AIM: To explore the expression of the transient outward potassium channel genes in diabetic rabbits ( DM ) after myocardial infarction ( MI ).METHODS: New Zealand rabbits were fed with high - fat and high - sucrose diet in the first 2 months and then intravenously injected with alloxan ( ALX ) ( 80 mg/kg ) to induce DM.All survived rabbits were randomly divided into 3 groups: DM + MI group, DM group and control group.Left anterior descending branch of coronary artery was ligated to induce MI.The mRNA expression levels in the myocardium of left ventricle ( LV ) were measured by real - time fluorescence - based RT - PCR.Data were calculated using 2-ΔΔct( threshold cycle ) method.RESULTS: Compared with control group, the mRNA levels of Kv4.3 and Kv4.2 were significantly down - regulated, whereas Kv1.4 were up - regulated ( P ＜0.05 ) in both DM + MI group and DM group.Compared with DM group, the mRNA levels of Kv4.3 and Kv4.2 in DM + MI group were significantly down - regulated ( P ＜ 0.05 ), whereas Kv1.4 was not significantly changed ( P ＞0.05 ).CONCLUSION: Transcriptional regulation in the post - MI remodeled diabetic rabbit LV myocardium is distinct for each potassium channel subunit and might be associated with the post - MI ventricular arrhythmias.%目的:探讨糖尿病合并心肌梗死后兔心室肌钾离子通道蛋白基因表达的变化.方法:选择新西兰兔作为研究对象,通过高脂高糖喂养2个月后由耳缘静脉注射四氧嘧啶(80 mg/kg)制作糖尿病模型,成模后改为普通饲料继续单笼喂养4个月,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2个月后处死,取左心室梗死周围区心室肌采用实时荧光定量PCR方法观察心肌钾离子通道蛋白Kv4.2、Kv4.3和Kv1.4 mRNA表达变化.结果:糖尿病+心肌梗死组和糖尿病假手术组兔心室肌Kv4.2和Kv4.3 mRNA表达均显著低于非糖尿病假手术组(P<0.05);而Kv1.4显著高于非糖尿病假手术组(P<0.05).糖尿病+心肌梗死组兔心室肌Kv4.2和Kv4.3 mRNA表达显著低于糖尿病假手术组(P<0.05);而Kv1.4并无显著升高(P>0.05).结论:糖尿病兔心肌梗死后瞬时外向钾离子通道蛋白基因表达发生了改变即电重构,这可能是心肌梗死后室性心律失常易感性增加的机制之一.
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