Comparison Between the protective Effects of Etomoxir and Ranolazine on Infarct Size in the Isolated Ischemic Rat Heart

Some studies have shown the protective effects of Etomoxir and Ranolazine in the hypoxic and ischemic condition of the heart. However, at present, there has not been any comparative study between the effects of Etomoxir and Ranolazine onischemia/reperfusion injuries (esp. infarct size), So their effects on infarct size in the ischemic isolated rat heart were studied and compared. Isolated rat hearts were divided into 3 groups randomly (n=6 in each group) and mounted on a Langendorff apparatus then perfused by a modified Krebs-Henseleit solution. In control group, the hearts were perfused by the solution at stabilization, 30min regional ischemia and 120min reperfusion while in the test groups they were perfused by enriched Krebs solution with 1μM of Etomoxir or 20μM of Ranolazine during ischemia/reperfusion. At the end of reperfusion, Evans Blue solution was infused to stain the non-ischemic area. Then the heart was incubated in 1% thriphenyl tetrazolium chloride solution and fixed by formalin. The infarct size was determined by a computerized planimetry package. The results showed that Etomoxir results in the significant decrease in the size of infracted area. In the control group, infarct size was 6.3±2.9%, while Etomoxir reduced infarct size to 20.9±5% (p< 0.01). Perfusion of the hearts by Ranolazine enriched Krebs solution produced greater reduction in infarct size (16.4±3.6%, p< 0.001). The effect was not statistically significant between the test groups. It seems that Etomoxir (an inhibitor of fatty acid uptake by mitochondria) and Ranolazine (an inhibitor of fatty acid oxidation by mitochondria) probably, by indirect increasing of glucose oxidation, duning ischemia and reperfusion, may improve reperfusion recovery of ischemic heart and reduce infarct size. The results showed protective effects of Etomoxir and Ranolazine on infarct size without any significant difference between them.