OBJECTIVETo compare two rat models of myocardial infarction established by coronary artery ligation and harmonic scalpel method for their advantages, disadvantages and applications.

METHODSSixty Sprague Dawley rats were randomly divided into sham-operated group, coronary artery ligation group and harmonic scalpel group. In the latter two groups, myocardial infarction was induced by ligation of the left anterior descending coronary artery and coagulation of the artery, respectively. Four weeks after the operations, the rats were sacrificed to measure the serum levels of CK, CK-MB, LDH and AST, and the hearts were collected for histopathological observation with HE staining.

RESULTSThe rats in the sham-operated group and coronary artery ligation group showed no significant differences in serum levels of CK , CK-MB , LDH or AST. Histologically, the myocardial tissues of the two models all showed coagulation necrosis and inflammatory cell infiltration, with granulation tissue ingrowth in the infracted tissues and scar formation. The mortality rate of the rats in coronary artery ligation group was 50% at 4 weeks, significantly higher than that of the harmonic scalpel group (20%, P<0.05).

CONCLUSIONCoronary artery ligation and harmonic scalpel method are both effective means to produce rat models of myocardial infarction. The latter method can establish a more stable model for studying the mechanism and treatment of myocardial infarction.