Effects of L-Carnitine on Cardiac Apoptosis in Ischemic-Reperfused Isolated Rat Heart

Carnitine is a vital biologic substance for transporting fatty acids into myocytes. It also facilitates fatty acids -oxidation for energy production. In this study, effects of L-carnitine (L-Car) on apoptosis in the ischemic isolated rat heart were investigated. Male Sprague-Dawley rats were divided into four groups and anesthetized by sodium pentobarbital. The heart was removed and mounted on a Langendorff apparatus then perfused by a modified Krebs-Henseleit (K/H) solution under a constant pressure at 37 °C. In the control group, the hearts were perfused only by normal K/H solution at stabilization, 30 min. regional ischemia and 120 min. reperfusion, while in each of the test groups, the hearts were perfused during ischemia-reperfusion with 0.5, 2.5 and 5 mM of L-Car-enriched K/H solution, respectively. At the end of reperfusion, immunohistochemical detection of apoptotic cells was performed by using an in situ apoptosis detection kit. The number of TUNEL-positive cardiomyocytes was counted in five random high-power fields in each sample. In the control group, the number of apoptotic cells were 48±3 while addition of L-Car (0.5, 2.5 and 5 mM) to the solution reduced the number of apoptotic cells to 6±1, 4±1 and 3±1, respectively (p<0.001 for all concentrations). There was no significant difference between and within test groups using ANOVA one-way. Considering these results, we conclude that L-Car has a protective effect against cardiac ischemia-reperfusion induced injuries as a reduction of apoptotic cardiomyocytes.