The investigations of effects of melatonin, quercetin and resveratrol on streptozotocin-induced diabetic nephropathy in wistar albino rats

Their role of oxygen radicals are known in the pathogenesis of kidney damage. The studies have shown that diabetes accelerates the formation of ROS. The aim of the present study was to examine the antioxidative effects of melatonin, quercetin and resveratrol on STZ-induced diabetic nephropaty in rats.In this study, weighing 300-360 g 47 Wistar albino male rats which were provided from Inonu University Laboratory Animals Research Center were used. The experimental objects were divided into 5 groups randomly: Group 1: Control, Group 2: Diabetes (STZ 45 mg/kg/single dose/ip), Group 3: Diabetes + Melatonin (10 mg/kg/day/ip for 30 days), Group 4: Diabetes + Quercetin (25 mg/kg/day/ip for 30 days), Group 5: Diabetes + Resveratrol (10 mg/kg/day/ip for 30 days). Blood glucose levels and weights of all rats were measured at the beginning, at the middle and at the end of study. At the end of the 30 days experiment, rats were sacrified under ketamine anesthesia. Pancreas and kidney tissues were removed. Left kidneys and pancreas were used for histological analysis and right kidneys were used for biochemical analysis. The tissue samples were fixed in 10% formalin and were embedded in paraffin. Sections of the tissue were cut at 5 µm, mounted on slides, stained with Hematoxylin-eosin (H-E), Periodic acid Schiff (PAS), Toluidin blue and TGF-ß1and assessed on Leica DFC 280 light microscopy.In diabetic group,blood glucose levels were increased and body weights were decreased compared to the control group. Histopathological changes were observed in the kidney tubules and glomerulus. Tubules were detected that epithelial desquamation, swelling, intracytoplasmic vacualization, loss of microvilli and peritubuler infiltration in the tubules. Glomerular basement membrane thickning and sclerotic changes were observed. In this group, TGF-ß1 stained cells were evident. Biochemical analyzes; results of diabetic rats showed that MDA level was increased while SOD and CAT activities were decreased compared to the control group. Administrations of melatonin, quercetin and resveratrol were reduced the renal injury in diabetic rats. Fasting blood glucose levels of these groups were decreased significantly when compared to diabetic group. Tubuler and glomerular changes were significantly reduced when compared to diabetic group. In addition, in the biochemical analyzes; SOD and CAT activities were increased while MDA level was significantly decreased when compared to the diabetic group.In this study, oxidative stress plays a role in kidney injury caused by diabetes mellitus in rats, on the other hand administration of melatonin, quercetin and resveratrol were shown to be effective in reducing oxidative stress. As a result, we suggest that all of the therapeutic agents we administered are beneficial in the treatment of kidney damage induced by diabetes mellitus via supporting antioxidant defence system.