犬急性心肌梗死早期冠状动脉旁路移植术对梗死周边区心肌离子通道蛋白表达的影响

Effect of Early Coronary Artery Bypass Graft Surgery on Expression Level of Ionophorous Protein at Infracted Border Zone in Dog with Acute Myocardial Infarction

目的探讨犬急性心肌梗死早期冠状动脉旁路移植术对梗死周边区心肌离子通道蛋白表达的影响及其意义。方法选取健康杂种犬30只制备动物模型,结扎犬冠状动脉前降支,以其支配区域的心肌颜色明显变暗作为心肌梗死模型手术成功的判定标准。分别在心肌梗死后不同时间点行冠状动脉旁路移植术作为实验组(1周、2周、4周、6周);并对每个时间点分别设立对照组(心肌梗死不行冠状动脉旁路移植术)。取未结扎冠状动脉相应区域的心肌组织作为正常组。8周后切取实验组及对照组心肌标本。采用逆转录-聚合酶链反应(RT-PCR)方法检测实验组心脏正常心肌、心肌梗死周边区心肌及对照组相应部位的心肌组织中离子通道蛋白Cav1.2、Kv4.3及Kch IP2 m RNA表达水平。结果每个实验组各存活4只,对照组均存活。对照组心肌三种离子通道蛋白Cav1.2、Kv4.3及Kch IP2 m RNA表达明显低于正常及实验组心肌(P<0.01);4周、6周实验组Cav1.2m RNA表达明显低于正常组(P<0.05);4周、6周实验组Kv4.3及Kch IP2 m RNA表达明显低于正常组及1周、2周实验组(P<0.05)。结论犬急性心肌梗死早期冠状动脉旁路移植术可以减轻离子通道蛋白表达的变化,尤其2周内冠状动脉旁路移植术可最大限度改善离子通道蛋白的表达,减少缺血对梗死周边区心肌离子通道蛋白的影响,减少缺血对梗死周边区心肌电生理的影响。

Objective To investigate the effect and significance of early coronary artery bypass graft(CABG)on the expression level of ionophorous protein at infracted border zone(IBZ) in dog with acute myocardial infarction.Methods The anterior descending coronary artery of all thirty healthy mongrel dogs were ligated into myocardial infarction model,whose successful criteria was that the regional myocardium supplied by ligated coronary artery became darker.Coronary artery bypass surgery performed at different time points after myocardial infarction(in the 1 st week,the2 nd week,the 4th week,the 6th week respectively) was as an experimental group.While myocardial infarction without coronary artery bypass surgery was set up as a control group.Myocardial tissue without ligation of coronary artery was as a normal group.After 8 weeks,myocardial specimens were cut out in the experimental group and the control group.The local expression levels of ionophorous proteins such as Cavl.2,Kv4.3 and KchIP2 mRNA were detected by means of reverse transcription- polymerase chain reaction(RT-PCR) at normal myocardium and IBZ of the experimental group and the control group.Results Four dogs in every experimental group and all dogs in the control group survived to the end of the study.Three myocardial ion channel proteins expression in the control group were lower than those of the normal group or the experimental group significantly(P<0.01).Cavl.2 mRNA expression in the experimental group in the 4th week or the 6th week was lower than that in the normal group significantly(P<0.05).Kv4.3 and KchIP2 mRNA expression in the experimental group in the 4th week or the 6th week were lower than those in the normal group and the experimental group significantly in the 1st week or the 2nd week(P<0.05).Conclusion Early CABG surgery for acute myocardial infarction could lessen the changes of expression level of ionophorous protein at infracted border zone(IBZ)of dog with acute myocardial infarction.Especially,CABG surgery among two weeks could improve expression level of ionophorous protein,and reduce the effect of ischemia for ionophorous protein and myocardial electrophysiology at IBZ.