ABSTRACT
BACKGROUND: Exposure to high altitude in hypobaric hypoxia (HH) is considered to be a physiological oxidative/nitrosative stress. Quercetin (Que) is an effective antioxidant and free radical scavenger against oxidative/nitrosative stress. AIMS: The aim of this study was to investigate the cardioprotective effects of Que in animals exposed to intermittent HH (IHH) and therefore exposed to oxidative/nitrosative stress. MATERIALS AND METHODS: Wistar albino male rats were exposed to short-term (2 days) or long-term (4 weeks; 5 days/week) IHH in a hypobaric chamber (5,500 m, 8 h/day, 380 mmHg, 12% O2, and 88% N2). Half of the animals received natural antioxidant Que (body weight: 30 mg/kg) daily before each IHH exposure and the remaining rats received vehicle (carboxymethylcellulose solution). Control rats were kept under normobaric normoxia (Nx) and treated in a corresponding manner. One day after the last exposure to IHH, we measured the cardiac hypoxia-induced oxidative/nitrosative stress biomarkers: the malondialdehyde (MDA) level and protein carbonyl (PC) content, the activity of some antioxidant enzymes [superoxide dismutase (SOD) and catalase (CAT)], the nitrite plus nitrate (NOx) production, and the inducible nitric oxide synthase (iNOS) protein expression. RESULTS: Heart tissue MDA and PC levels, NOx level, and iNOS expression of IHH-exposed rats had increased, and SOD and CAT activities had decreased compared with those of the Nx-exposed rats (control groups). MDA, CP, NOx, and iNOS levels had decreased in Que-treated IHH-exposed rats compared with IHH-exposed rats (control groups). However, Que administration increased SOD and CAT activities of the heart tissue in the IHH-exposed rats. CONCLUSION: HH exposure increases oxidative/nitrosative stress in heart tissue and Que is an effective cardioprotective agent, which further supports the oxidative cardiac dysfunction induced by hypoxia.
Subject(s)
Antioxidants/pharmacology , Heart/drug effects , Hypoxia/physiopathology , Nitrosative Stress/drug effects , Oxidative Stress/drug effects , Quercetin/pharmacology , Altitude , Animals , Male , Rats , Rats, WistarABSTRACT
Diabetic neuropathy (DN) is a frequent, serious and debilitating chronic complication of diabetes mellitus (DM). Hyperglycemia, oxidative and nitrosative stress are involved in causing nerve damage in several animals, humans and experimental models of diabetes. This study was designed to investigate the synergistic cumulative neuroprotective effect of quercetin administration and moderate exercise training on sciatic nerves injuries in streptozotocin (STZ)-diabetic rats. DM was induced in Wistar rats by intraperitoneal administration of STZ (60 mg/kg). The diabetic rats received quercetin (30 mg/kg body weight/day) and performed an exercise training program (30 minutes/day, 5 days/week) for 5 weeks. Various biochemical parameters of oxidative and nitrosative stress were determined and histopathological evaluations were performed from sciatic nerves. Diabetic rats showed significantly increased oxidative and nitrosative stress parameter levels in the sciatic nerves. Diabetic trained rats treated with quercetin exhibited a significantly reduced hyperglycemia and its metabolic abnormalities induced by intraperitoneal administration of STZ. Histological alterations of the sciatic nerves induced after STZ administration were restored by administration of quercetin. Quercetin administration in association with moderate exercise training not only attenuated the diabetic condition but also restored sciatic nerves injuries by controlling hyperglycemia to down-regulate the generation of free radicals, as well as the elevation of antioxidant enzymes.
Subject(s)
Antioxidants/therapeutic use , Diabetes Mellitus, Experimental/therapy , Physical Conditioning, Animal , Quercetin/therapeutic use , Sciatic Nerve/injuries , Animals , Antioxidants/pharmacology , Catalase/metabolism , Diabetes Mellitus, Experimental/complications , Diabetes Mellitus, Experimental/metabolism , Diabetes Mellitus, Experimental/pathology , Male , Nitric Oxide Synthase Type II/metabolism , Nitrites/metabolism , Quercetin/pharmacology , Rats, Wistar , Sciatic Nerve/drug effects , Sciatic Nerve/metabolism , Sciatic Nerve/pathology , Superoxide Dismutase/metabolismABSTRACT
Background To investigate the protective effects of Quercetin administration associated with chronic moderate exercise (training) on oxidative stress in the liver in streptozotocin-induced diabetic rats. Methods Diabetic rats that performed exercise training were subjected to a swimming training program (1 hour/day, 5 days/week, 4 weeks). The diabetic rats received natural antioxidant, Quercetin (20 mg/kg body weight/day) for 4 weeks. At the end of the study, all animals were sacrificed and liver samples were collected for estimation: some oxidative stress markers (malondialdehyde, MDA and protein carbonyls groups, PC), the activity of antioxidant enzymes (superoxide dismutase, SOD and catalase, CAT), reduced glutathione (GSH) level and reduced (GSH) and oxidized (GSSG) glutathione ratio. Results Diabetic rats submitted to exercise training showed significantly increased the oxidative stress markers (MDA and PC) and a reduction of antioxidant enzyme (SOD and CAT) activity, GSH level and GSH/ GSSG ratio in hepatic tissues. A decrease in the levels of oxidative stress markers associated with elevated activity of antioxidant enzymes, the GSH level and GSH/GSSG ratio in the hepatic tissue were observed in Quercetin-treated diabetic trained rats. Conclusions These findings suggest that Quercetin administration in association with chronic moderate exercise exerts a protective effect in diabetes by attenuating hyperglycemia-mediated oxidative stress in hepatic tissue.