Preventive effect of caffeic acid on lysosomal dysfunction in isoproterenol-induced myocardial infarcted rats.

We evaluated the preventive effect of caffeic acid (CA) on lysosomal enzymes in isoproterenol (ISO)-treated myocardial infarcted rats. Male albino Wistar rats were pretreated with CA (15 mg/kg) daily for a period of 10 days. After the pretreatment period, ISO (100 mg/kg) was subcutaneously injected to rats twice at an interval of 24 h. The activity of serum creatine kinase-MB and lactate dehydrogenase was increased significantly (P < 0.05) in ISO-induced myocardial infarcted rats. The levels of plasma thiobarbituric acid reactive substances and lipid hydroperoxides were significantly (P < 0.05) increased, and the level of plasma-reduced glutathione was significantly (P < 0.05) decreased in ISO-induced myocardial infarcted rats. The activities of lysosomal enzymes (beta-glucuronidase, beta-N-acetylglucosaminidase, beta-galactosidase, cathepsin-B and cathepsin-D) were increased significantly (P < 0.05) in the serum and heart of ISO-induced myocardial infarcted rats. ISO induction also resulted in decreased stability of membranes, which was reflected by lowered activities of beta-glucuronidase and cathepsin-D in different fractions except cytosol. Pretreatment with CA (15 mg/kg) to ISO-treated rats significantly (P < 0.05) prevented the changes in the activities of cardiac marker enzymes, the levels of lipid peroxidation products, reduced glutathione and the activities of lysosomal enzymes in the serum, heart, and subcellular fractions. Oral treatment with CA (15 mg/kg) to normal control rats did not show any significant effect. Thus, the results of our study showed that CA prevented the lysosomal membrane damage against ISO-induced myocardial infarction. The observed effects of CA are due to membrane-stabilizing, antilipo peroxidative, and antioxidant effects.