ABSTRACT
Objective To investigate the effect and significance of early coronary artery bypass grafting (CABG) on the expression level of nerve-related 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 experimental 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 remodelling at IBZ.Especially CABG surgery two weeks after MI could lessen the sympathetic maximacily.