Effects of melatonin on atherogenic index, oxidative stress, vaspin, visfatin levels and endothelium-dependent relaxation responses in experimental hypercholesterolemia

2.ABSTRACT Effects of Melatonin on Atherogenic Index, Oxidative Stress, Vaspin, Visfatin Levels and Endothelium-Dependent Relaxation Responses in Experimental Hypercholesterolemia Hypercholesterolemia, characterized by nitric oxide (NO) bioavailability, lipid profile and oxidative stress changes, is one of the important risk factors for atherosclerosis. In this study, it was aimed to investigate effects of melatonin on lipid parameters, atherogenic index, ADMA, MDA, GSH levels, SOD activites, liver function tests, contractions of resulting in vitro 1 adrenergic stimulation and endothelium-dependent relaxation responses, vaspin-visfatin levels in liver and aorta and also effects on histopathological changes in high-cholesterol diet-induced hypercholestremia. Also, effects of melatonin on these parametres were compared with atorvastatin. Rats were divided into 5 groups (n:7). While Control group was fed with normal diet, other groups were fed with % 2 cholesterol and % 0.5 cholic acid diet for 8 weeks. Melatonin was administrated both concurrently with cholesterol and only last 2 weeks. Atorvastatin (10 mg/kg) was administered by gavage only last 2 weeks. At the end of the experiment Phe-Ach responses from isolated thoracic aorta rings were recorded. Serum lipid parameters and liver function tests were measured in the autoanalyser according to appropriate kit protocol. Histopathological examinations were performed in liver, kidney and aorta tissues. The tissue, MDA, GSH levels; SOD activities were determined by spectrophotometry, vaspin and visfatin levels were detected by Western-Blot and serum ADMA levels were measured by HPLC. Rising lipid parameters, atherogenic index, liver function tests, ACh EC50 values ADMA levels and oxidative changes cause of hypercholesterolemia, decreased with melatonin and atorvastatin treatment. The changes of vaspin, visfatin levels in liver and aorta tissues were decreased by treating melatonin and atorvastatin treatments in hypercholestremia group. It is thought to melatonin may have protective and therapeutic effect on hypercholestremia, and create similar effects with atorvastatin and test clinically. Key words: hypercholesteremia, melatonin, ADMA, oxidative stress, vaspin visfatin,