title: Protective effect of melatonin on beta-cell damage in streptozotocin-induced diabetes in rats.
abstract: The aim of the present study was the evaluation of possible protective effects of melatonin against beta-cell damage in streptozotocin-induced diabetes in rats. Malondialdehyde levels and glutathione peroxidase activity were measured in pancreatic homogenates. Pancreatic beta-cells were examined by immunohistochemical methods. Streptozotocin was injected intraperitoneally at a single dose of 60 mg/kg for induction of diabetes. Melatonin (200 microg/kg/day, ip) was injected for 3 days prior to administration of streptozotocin; these injections were continued until the end of the study (4 weeks). Streptozotocin induced a significant increase in malondialdehyde levels (p < 0.01) and a significant decrease in glutathione peroxidase activity (p < 0.05) in pancreatic tissue. Degeneration of islet cells and weak immunohistochemical staining of insulin was observed in diabetic rats. Treatment of diabetic rats with melatonin markedly reduced malondialdehyde production (p < 0.05) and increased glutathione peroxidase activity (p < 0.01) without affecting hyperglycemia. Increased staining of insulin and preservation of islet cells were apparent in the melatonin-treated diabetic rats. These data suggest that melatonin treatment has a therapeutic effect in diabetes by reduction of oxidative stress and preservation of pancreatic beta-cell integrity.
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D015992:Body Mass Index; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000473:pathology / Q000517:prevention & control*; D007515:Islets of Langerhans / Q000473:pathology*; D008297:Male; D008550:Melatonin / Q000627:therapeutic use*; D051381:Rats
chemical_list: D001786:Blood Glucose; D008550:Melatonin