Attenuation of Infarct Size by Leucas aspera in Ischemia-Reperfusion Induced Myocardial Infarction in Rats

Abstract Background: The chronic administration of aqueous and alcoholic extracts of Leucas aspera (L. aspera) was evaluated for protection against ischemia–reperfusion (I/R) induced myocardial infarction in rats. Methods: Aqueous and alcoholic extracts of L. aspera were administered orally to wistar albino rats (200 – 250 g) in three different doses (100, 250 and 500 mg kg-1), by gastric gavage for one week. At the end of this period, control (I/R) group and experimental groups were subjected to 30 min occlusion of the left anterior descending coronary artery and thereafter reperfused for 4 h. Infarct size was measured by using the staining agent 2,3,5- triphenyl tetrazolium chloride (TTC). Results: Ischemia – reperfusion induced cardiac necrosis was evidenced by elevated levels of the serum marker enzymes such as SGOT, SGPT LDH, CK-MB and CK and lipid peroxides in serum and heart tissue, increased levels of myeloperoxidase (MPO) in heart tissue. Oxidative damage was further evidenced by decreased levels of antioxidative enzymes SOD, CAT, GST and GSH in the hearts subjected to in vivo myocardial ischemia - reperfusion injury. The pretreatment with L. aspera produced a significant reduction in infarct size and decreased levels of lipid peroxides in serum and heart tissue. The plant extract dose dependently inhibited the rise in serum marker enzymes and antagonized the reduction in antioxidant enzymes in heart tissue. Conclusion: The present study clearly indicates that L. aspera by neutralizing the cytotoxic free radicals generated during I/R injury, thereby protects the loss of membrane integrity and stabilizing the membrane, hence protects the myocyte from oxidative stress. This is further conformed by the reduced levels of myeloperoxidase indicating that pretreatment with aqueous and alcoholic extracts suppressed neutrophil infiltration into the injured myocardium and protects rat heart against ischemia-reperfusion induced myocardial infarction. Ke