Ação da melatonina exógena na cirrose hepática experimental e seus efeitos sobre o rim e baço de ratos albinos

Abstract

Cirrhosisis a chronic and progressive disease, being responsable for a high mortality rate in the world. Of complex pathological condition, at na advanced stage, several organs are damaged and the Picture becomes irreversible, reason why diverse studies search new therapeutic options for this disease. For meatonin to be mentioned in theliterature as a potent antioxidant agent capable of regulating several physiological processes in mammals, we aimed to evaluate the effect of this hormone in the liver, kidney and spleen of animals induced liver cirrhosis. For this, 25 albino rats, 60 days old, were randomly divided into 5 groups: Group I – control rats; Group II – rats induced the hepatic cirrhosis with thioacetamide for 8 weeks; Group III: - rats induced hepatic cirrhosis with thioacetamide and treated with melatonin simultaneously for 8 weeks; Group IV - rats induced hepatic cirrhosis with thioacetamide for 8 weeks and then treated with melatonin for another eight weeks; Group V - rats induced hepatic cirrhosis with thioacetamide for 8 weeks and maintained for eight weeks without melatonin. Cirrhosis was induced with three weekly applications of thioacetamide at the dosage of 200 mg / kg intraperitoneally. Melatonin was administered daily at a dosage of 20 mg / kg for 8 weeks, by the same route of administration. Histopathological, histochemical, immunohistochemical, collagen measurements, nitric oxide levels, biochemical analyzes of liver and renal function, renal morphometry, hemogram and analysis of tissue oxidative stress were performed. The results showed that melatonin bound as a repairer and protector against cirrhosis maintaining the morphological characteristics of the liver, as well as avoiding fibrosis. In addition, it maintained the levels of glucose and enzymes AST, ALT, gamma-glutamyl transferase, alkaline phosphatase, albumin, globulin and total protein. It prevented the increase of lipid in the liver, increased GSH, reduced lipid peroxidation and levels of proinflammatory cytokines and apoptotic index. As for the kidneys and spleens, melatonin also prevented and improved the effects of cirrhosis on these organs, maintaining the structure and function of the renal glomeruli, as well as the hematological profile. It also increased GSH, reduced lipid peroxidation and proinflammatory cytokine levels. Thus, it is concluded that melatonin acts not only in a protective way against cirrhosis but also reduces the damage caused by this pathology in the hepatic, renal and splenic tissues.