ABSTRACT
Objective To investigate the effect of diabetes mellitus (DM) on adenosine postcondi-tioning-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 ran-dom number table: sham operation group (DS group), I∕R group (DI∕R group) and adenosine postcondi-tioning 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 postcon-ditioning group (NAP group). Myocardial I∕R was induced by 30 min occlusion of the left anterior descend-ing 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 im-mediately 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 postcondition-ing in rats.