Effects of Melatonin on the Oxidative Stress Parameters, Dimethylarginine on Dimethylaminohydrolase and Histopathological Changes in Experimental Hypercholesterolemia

Abstract

Objectives: In this study, it was aimed to investigate the effects of melatonin on oxidative stress\rparameters, expression levels of dimethylarginine dimethylaminohydrolase (DDAH) which involved\rin nitric oxide metabolism, and histopathological changes in the liver tissue in experimental\rhypercholesterolemia.\rMaterial and Methods: Rats were divided into 4 groups: a) Control, b) Hypercholesterolemia\r(HCT), c) Melatonin administrated concurrently with cholesterol diet (HCT-MEL, prophylactically),\rd) Melatonin administrated only during the last 2 weeks of cholesterol diet feeding (HCT-2MEL,\rtherapeutically) groups.\rResults: Although an increase was observed in the MDA levels, the DDAH protein expression and\rGSH levels were found to decrease with hypercholesterolemia. MDA levels, GSH activity and\rDDAH expression were normalized with melatonin administrations. Significant changes such as\rsinusoidal congestion, cloudy bloating, periportal cell infiltration, periacinary lubrication, and\rapoptosis were observed in the liver tissue by hypercholesterolemia. In the HCT-MEL group, the\rseverity of the fat in the periportal and midzonal region was lowere compared to the HCT group.\rHistopathologically when the two treatment groups are compared, prophylactic melatonin was more\reffective than its therapeutic use.\rConclusion: Melatonin may be a hepatoprotective and/or therapeutic agent with antioxidant effect,\rand regulator of nitric oxide metabolism in prevention of histopathological changes in liver\rpathology in diet-induced hypercholesterolemia.