Effects of Quercetin and Chronic (Training) Exercise on Oxidative Stress Status in Animals with Streptozotocin-Induced Diabetes

Abstract

Increasing evidence in both experimental and clinical studies suggests that oxidative stress is involved in the pathogenesis and progression of diabetic tissue damage. This study investigated the effects of chronic exercise training associated with chronic oral administration of Quercetin on blood glucose levels and oxidative stress status in streptozotocin-induced diabetic Wistar rats. Adult male Wistar rats were divided into seven groups: Group I: non-diabetic, sedentary control rats; Group II: non-diabetic, trained control rats; Group III: non-diabetic, trained control rats treated with Quercetin; Group IV: diabetic, sedentary control rats; Group V: diabetic, trained control rats; Group VI: diabetic, sedentary rats treated with Quercetin; Group VII: diabetic, trained rats treated with Quercetin. Quercetin was administered via an intragastric tube (0.6 ml/rat), at a dose of 20 mg/kg body weight/day for 4 weeks after the induction of diabetes mellitus. Diabetes was induced by a single i.p. injection of streptozotocin (40 mg/kg body weight). Animals were sacrificed at the end of a 4-week swimming training program (1 hour/day, 5 days/week, 4 weeks). The glycemic profile, oxidative status (lipid peroxidation and protein oxidation) and antioxidant levels (superoxide dismutase, catalase and reduced glutathione) were evaluated. When compared to diabetic sedentary rats, the animals submitted to chronic exercise presented significantly lower glycaemic values, and significantly increased oxidative stress levels. The diabetic, trained rats treated with Quercetin presented significantly lower glycaemic values accompanied by a remarkable reduction of oxidative markers. The results suggested that chronic exercise training associated with Quercetin administration could lower blood glucose levels and reduce oxidative stress in in streptozotocin-induced diabetic rats.