Protective effects of Diemailing Injection on experimental myocardial infarction in rats and its mechanism

Objective To observe the protective effects of Diemailing Injection(DMLI) on experimental myocardial infarction in rats and its mechanism.Methods The experimental myocardial infarction model was induced by left anterior descending coronary occulusion for 24 h in rats.The rats were randomly divided into sham group,myyocardial infaction model group,DMLI groups with different doses(2.5,5.0,10.0 mL·kg~(-1))(n=20).The changes of myocardial infarction size(MIS),aspartate aminotransferase(AST),actate dehydrogenase(LDH),creatine phosphokinase(CK),superoxide dismutase(SOD) and glutathione peroxidase(GSH-Px) activities and malondialdehyde(MDA) content in serum,endothelin(ET) and angiotensinⅡ(AngⅡ) levels in plasma,and low shearing specific viscosity,middle shearing specific viscosity and high shearing specific viscosity of blood and specific viscosity of plasma were determined.At the same time,myocardial free fatty acid(FFA) contents of infarction and noninfarction area were determined.Results In rats treated by DMLI(in doses of 2.5,5.0 and 10.0 mL·kg~(-1) i.v after coronary occulusion),the MIS was significantly reduced(P0.05 or P0.01),the AST,LDH and CK activities in serum,the ET and AngⅡ levels in plasma,and viscosity of blood and plasma were declined((P0.05) or P0.01),while SOD and GSH-Px activities in serum were increased significantly(P0.05 or P0.01).In addition,myocardial FFA contents of infarction and noninfarction area were decreased markedly(P0.05 or(P0.01).)Conclusion DMLI has protective effects on experimental myocardial infarction,which may be related to improving myocardial metabolism,increasing the activity of antioxidize,eliminating the free radicals,decreasing ET and AngⅡ levels in plasma,and decreasing blood viscosity etc.