Effect of diabetes mellitus on adenosine postconditioning-induced reduction of myocardial ischemia-reperfusion injury in rats

Abstract

Objective To investigate the effect of diabetes mellitus (DM) on adenosine postconditioning-induced reduction of myocardial ischemia-reperfusion (I/R) injury in rats. Methods Adult male Sprague-Dawley rats, weighing 230-260 g, were used in the study.Type 2 DM was induced by high-fat diet and intraperitoneal l% streptozocin 35 mg/kg and confirmed by fasting blood glucose concentration>16.7 mmol/L 72 h later.Eighteen rats with type 2 DM were divided into 3 groups (n=6 each) using a random number table: sham operation group (DS group), I/R group (DI/R group) and adenosine postconditioning group (DAP group). Eighteen healthy nondiabetic rats were selected and randomly divided into 3 groups (n=6 each): sham operation group (NS group), I/R group (NI/R group) and adenosine postconditioning group (NAP group). Myocardial I/R was induced by 30 min occlusion of the left anterior descending branch of coronary artery followed by 2 h of reperfusion.Venous blood samples were collected from the femoral vein at 2 h of reperfusion for measurement of plasma cardiac troponin I (cTnI) and creatine kinase-MB (CK-MB) concentrations (by enzyme-linked immunosorbent assay). The rats were then sacrificed immediately after blood sampling for determination of the myocardial ischemic area and infarct size. Results The plasma cTnI and CK-MB concentrations were significantly increased, and the percentage of myocardial infarct size was increased after myocardial I/R in nondiabetic and diabetic rats.Adenosine postconditioning significantly decreased plasma cTnI and CK-MB concentrations and percentage of myocardial infarct size in nondiabetic and diabetic rats (P<0.05). Compared with group NAP, the plasma concentrations of cTnI and CK-MB were significantly increased, and the percentage of myocardial infarct size was increased in group DAP (P<0.05). Conclusion DM can weaken cardioprotection induced by adenosine postconditioning in rats. Key words: Diabetes mellitus; Adenosine; Ischemic postconditioning; Myocardial reperfusion injury