Streptozotocin에 의해 유도된 당뇨 쥐의 췌장에 대한 Melatonin의 효과

Abstract

The effect of melatonin, a powerful antioxidant, on the pancreas of the diabetes mellitus induced by streptozotocin in male rats was studied. Diabetes was induced by the intraperitoneal injection of 65 mg of streptozotocin per kg of body weight. To know the effect of melatonin, total 10 mg of melatonin per kg of body weight was administered intraperitoneally at the time of streptozotocin and 72 hours after the first administration. Then the rats were sacrificed at the 7 th day after the first injection. Several biochemical parameters, microscopic examination and immunohistochemical stain were done. The injection of streptozotocin caused significant increases in the blood levels of glucose and hemoglobin A1C, and pancreatic levels of hydrogen peroxide and malondialdehyde. Streptozotocin treated group showed the decrease of islets and insulin-immunoreactive cells, and degenerated B cell granules. The injection of melatonin reduced the blood levels of glucose and hemoglobin A1C, and reduced pancreatic levels of hydrogen peroxide and malondialdehyde. Melatonin caused significant increases in the levels of total antioxidant status, superoxide dismutase and catalase. The melatonin treated group showed relatively well preserved cell organelles and Langerhan's islets under the microscopic examination. And the melatonin treated group showed the significant increase in number of insulin-immunoreactive cells compared with streptozotocin treated group under the immunohistochemical stain. These results may suggest that melatonin has a protective effect on the pancreatic islets in the diabetes induced by streptozotocin from oxidative damage by the increase of total antioxidant status via the increased activity of antioxidant enzymes.