Ameliorative potential of resveratrol on proinflammatory cytokines, hyperglycemia mediated oxidative stress, and pancreatic β-cell dysfunction in streptozotocin-nicotinamide-induced diabetic rats

Chronic exposure of pancreatic β‐cells to supraphysiologic glucose causes adverse β‐cell dysfunction. Thus, the present study was aimed to investigate the hypothesis that oral administration of resveratrol attenuates hyperglycemia, proinflammatory cytokines and antioxidant competence and protects β‐cell ultrastructure in streptozotocin‐nicotinamide‐induced diabetic rats. Oral administration of resveratrol (5 mg/kg body weight) to diabetic rats for 30 days showed a significant decline in the levels of blood glucose, glycosylated hemoglobin (HbA1c), TNF‐α, IL‐1β, IL‐6, NF‐κB p65 unit and nitric oxide (NO) with concomitant elevation in plasma insulin. Further, resveratrol treated diabetic rats elicited a notable attenuation in the levels of lipid peroxides, hydroperoxides and protein carbonyls in both plasma and pancreatic tissues. The diminished activities of pancreatic superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and glutathione‐S‐transferase (GST) as well as the decreased levels of plasma ceruloplasmin, vitamin C, vitamin E and reduced glutathione (GSH) in diabetic rats were reverted to near normalcy by resveratrol administration. Based on histological and ultrastructural observations, it is first‐time reported that the oral administration of resveratrol may effectively rescue β‐cells from oxidative damage without affecting their function and structural integrity. The results of the present investigation demonstrated that resveratrol exhibits significant antidiabetic potential by attenuating hyperglycemia, enhancing insulin secretion and antioxidant competence in pancreatic β‐cells of diabetic rats. J. Cell. Physiol. 224: 423–432, 2010. © 2010 Wiley‐Liss, Inc.