Protective Role of l-carnitine and melatonin in thioacetamide induced toxic hepatits models in rats

Oxidative stress plays important roles in most forms of liver diseases. Reactive oxygen metabolites play pivotal role in pathogenesis of oxidative stress. Excess reactive oxygen metabolites cause oxidative stress in hepatocytes and impair cellular functions. Reactive oxygen metabolites induced by oxidative stress can break down the cellular elements like lipid, protein and DNA and cause lipd peroxidation. Thioacetamide which is an experimental hepatotoxin causes oxidative stress and lipid peroxidation. L-carnitin and melatonin are known with their antioxidant and scavenging properties against free radicals. This study is designed to detect possible protective effects of L-carnitin and melatonin from oxidative stress in thioacetamide induced liver injury. 55 Wistar albino rats were included in this study. Rats were divided into 4 groups. Control groups were comprised of 10 rats and other groups were comprised of 15 rats. Group1: Control group which were given intraperitoneal saline. Group 2: Rats which were given intraperitoneal thioacetamide. Group 3:rats which were given intraperitoneal thioacetamide +melatonin Group 4: rats which were given intraperitoneal thioacetamide +L-carnitin. Blood samples were taken from all rats after completion of procedure for determination of serum aminotransferases (AST, ALT) and lactatedehydrogenase (LDH) and liver biopsies for determination of tissue malondialdehid ve reduced glutathione levels. Serum liver transaminases are higher in the study groups ( Group 2, 3 and group 4) than the control group(p ˂0.01). In group of rats which were given intraperitoneal thioacetamide +melatonin( Group 3) serum ALT and AST levels were lower than the group of rats which were given intraperitoneal thioacetamide alone( group) (p ˂0.39). In group of rats which were given intraperitoneal thioacetamide +L-carnitin.together ( group 4) ALT and AST levels were statistically lower than the group of rats which were given intraperitoneal thioacetamide ( group 2). (p ˂0.01). Mean MDA levels at the liver tissue were higher in group 2 than the control group. (p ˂0.21). Tissue MDA were higher in group 4 than the control group while lower in group 3. L-carnitin has been shown to be protective in rat models of toxic hepatitis by lowering serum transaminase levels statistically. Furthermore L-carnitin has been shown to protect liver tissue by partially lowering the damage caused by oxidative stress. Melatonin on the other hand has been shown to be partially protective from toxic injury by lowering serum transaminase levels. No significant protective effect of melatonin on oxidative stress could be shown.