ABSTRACT
Objective To investigate the protective effects of melatonin and possible mechanisms on rats with alco-holic fatty liver (AFL). Methods All rats were randomly divided into 4 groups: normal group (n = 10), model group (n = 12) and melatonin groups (10 mg / kg, 20 mg / kg; n = 10, respectively). The model of rats’ alcoholic fatty liver was induced by intragastric influsion of ethanol for 8 weeks. The melatonin groups’ rats received melato-nin by intraperitoneal injection after intragastric infusion of ethanol. Histopathological changes were evaluated by hematoxylin and eosin staining. The expressions of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were detected by immunohistochemical methods. The detection of aspartate aminotransferase (AST) levels and alanine transarninase (ALT) levels and the total bilirubin ( TBIL) levels in serum were provided by routine laboratory methods using an autoanalyzer. The levels of malondialdehyde ( MDA) and activities of glutathione peroxidase ( GPx) were measured by spectrophotometry. Results Compared with the normal group, the liver cells of the mod-el group showed obvious steatosis and significant swelling. However, less degree and less extensive of steatosis and swelling were observed in the melatonin groups. Compared with the normal group, the levels of ALT, AST and TBIL in serum and the levels of MDA in liver homogenates were significantly increased in the model group (P <0. 01), and the activities of GPx were distinctly decreased in the model group(P < 0. 01). But in the melatonin groups, the levels of ALT, AST and TBIL in serum and the levels of MDA in liver homogenates were decreased (P< 0. 01), and the activities of GPx were increased (P < 0. 01). Additionally, melatonin lessened the expression of TNF-α and IL-6 in liver obviously (P < 0. 01). Conclusion Melatonin may inhibit the development of alcoholic fatty liver and its possible mechanism is the ability to resist oxidative stress and lessen the expression of TNF-α and IL-6 and other relevant factors in liver.