ObjectiveTo 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. MethodsThe 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 1st week, the 2nd 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 Cav1.2, 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. ResultsFour 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). Cav1.2 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). ConclusionEarly 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.