Effect of myocardial insulin resistance on expression of p38MAPK in ischemic heart failure in rat / 中华胸心血管外科杂志

ABSTRACT

Objective This study was carried out to investigate the effect of myocardial insulin resistance on expression of p38 mitogen-activated protein kinase (MAPK) in ischemic heart failure in rat.Methods Male sprague-dawley rats were subjected either to ligation of the left anterior descending artery (LAD) (n =24) or to sham operation (n =24).After two weeks,cardiac size and function were determined by echocardiography.Glucose and fatty acid (FAO) oxidation rates as well as insulin response were measured in the isolated working heart.The protein expression of p38MAPK was evaluated by Western blotting.Results The infarcted hearts were dilated and had a reduced ejection fraction (ejection fraction ＜0.50).The basal glucose oxidation was preserved,but the fatty acid oxidation was significantly reduced.Insulin effect on substrate oxidation was significantly impaired for both the decrease in fatty acid oxidation and the increase in glucose oxidation.The protein expression of p38MAPK in infracted hearts wasfisigni cantly reduced(P＜0.05).Condusion Myocardial infarction in rats caused partial insulin resistance at the level of substrate oxidation,which was associated with cardiac contractile dysfunction and the expression of p38MAPK.