مطالعه اثرات پست كانديشنينگ ايسكميك و فارماكولوژيك ناشي از مصرف ال - كارنيتين بر روي اندازه انفاركت متعاقب ايسكمي - پرفيوژن مجدد در قلب ايزوله

Study of ischemic and pharmacologic postconditioning on infarct size in the ischemic reperfused isolated heart.

Objectives: In this study, effects of ischemic postconditioning (IPC) and pharmacologic postconditioning (PPC) by using L-Carnitine (L-Car) on infarct size in the ischemic-reperfused isolated rat heart were investigated and compared. Methods: Male rats were divided in five groups (control, IPC, and three PPC groups treated by L-Car) and were anesthetized by sodium pentobarbital (50 mg/kg-ip). Heart was removed and quickly mounted on a Langendorff apparatus and perfused by a modified Krebs-Henseleit (K/H) solution that was previously equilibrated with 95% O2-5% CO2. The hearts were subjected to 30 min regional ischemia followed by 120 min reperfusion. In the control and IPC groups, the hearts were perfused by normal K/H solution at stabilization, 30 min regional ischemia and 120 min reperfusion, while PPC groups were perfused by 0.5, 2.5 and 5mM of L-Car enriched K/H solution 10 min before and after reperfusion. At the end of reperfusion, infarct size was determined by triphenyltetrazolium chloride method and computerized planimetry. Results: Infarct size was decreased significantly in both IPC and PPC groups versus control. In control group, infarct size was 46.3±2.9 %, however, IPC reduced it to 22.6±1.5 % (p<0.001). Application of 0.5, 2.5 and 5mM of Car-enriched K/H solution 10 min before and after reperfusion in the PPC groups, reduced the infarct size from control group value to 41.8±4.0 (not significant), 28.1±2.0 (pO.OOl) and 25.4±3.9 % (pO.OOl), respectively. Except the effects of 0.5 mM L-Car, there was no significant difference between IPC and PPC groups on infarct size reduction. Conclusion: Considering the results, it may be concluded that IPC and PPC (by L-Car) have protective effects against cardiac I/R injuries by reduction of infarct size.