冠状动脉旁路移植术对犬急性心肌梗死心肌神经相关因子表达的影响

Effect of coronary artery bypass grafting on the expression level of nerve-related factor at myocardium in dogs 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神经相关因子表达的影响及其意义。方法结扎犬冠状动脉前降支制备心肌梗死模型（30只）。随机分为心肌梗死旁路移植实验组（22只）和心肌梗死不旁路移植对照组（8只）。分别在心肌梗死后1、2、4、6周行冠状动脉旁路移植术作为实验组，其中第2周4只，其余每组6只；对每个实验组分别设立心肌梗死不进行旁路移植对照组，每组2只。8周后开胸，分别切取实验组心脏正常心肌梗死周边区心肌及对照组相应部位的心肌。采用逆转录一聚合酶链反应（RT—PCR）方法检测梗死周边区心肌样本神经相关因子GAP43mRNA、NGFmRNA及SYNmRNA的表达水平及其变化。结果每个实验组各存活4只，对照组均存活。对照组GAP43mRNA、NGFmRNA及SYNmRNA表达明显高于实验组及正常心肌（P〈0．01）；第4、6周实验组GAP43mRNA、NGFmRNA表达明显高于1、2周实验组及正常心肌（P〈0．05）；实验组中SYNmRNA表达无统计学意义（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神经相关因子表达，减轻梗死周边区心肌交感神经重构，尤其2周内冠状动脉旁路移植术可以最大限度地减轻梗死周边区心肌交感神经重构。

Objective To investigate the effect and significance of early coronary artery bypass grafting （CABG） on the expression level of nerverelated factor at infracted border zone （ IBZ ） in dogs with acute myocardial infarction （AMI）. Methods The anterior descending coronary artery of all thirty dogs randomly assigned into experimental group （ n = 22 ） and control group （ n = 8 ） were ligated into MI model. The exper- imental group included those undergoing CABG 1 （n = 6 ） , 2 week （n = 4 ） , 4 week （n = 6 ） and 6 week （n = 6） after MI, and control group （n = 2） was established for every experimental group. We detected the local expression level of nerve-related factor such as GAP43 mRNA, NGF mRNA and SYN mRNA at normal myocardium and infracted border zone myocavdium by means of RT-PCR through thoracotomy at eight weeks after surgery. Results Four dogs of every experimental group and all dogs of control group survived to the end of the study. The local expression level of GAP43 mRNA, NGF mRNA and SYN mRNA in control groups was significantly higher than that in normal and experimental groups （P 〈 0.01 ）. The local expression level of GAP43 mRNA, NGF mRNA and SYN mRNA in 4 and 6 weeks bypass groups was significantly higher than that in normal and 1,2 weeks bypass groups （ P 〈 0.05 ）. There was no statistically significant the expression level of SYN mRNA among all experimental groups （ P 〉 0. 05 ）. Conclusions Early CABG surgery for AMI in dogs could lessen the expression level of nerve-related factor and the sympathetic remod- elling at IBZ. Especially CABG surgery two weeks afte.r MI could lessen the sympathetic maximacily.