Vascular impact of quercetin administration in association with moderate exercise training in experimental type 1 diabetes

Abstract

Hyperglycemia and oxidative stress have a major role in the pathogenesis of diabetic vascular complications. In this study, we investigated the efficacy of combining quercetin treatment with moderate exercise training in reversing diabetes-induced oxidative stress and ultrasound modifications in rat carotid arteries. The diabetic Wistar rats were divided into sedentary groups and trained groups. The trained animals went through a regular moderate exercise by swimming (5 weeks). Some non-diabetic and diabetic rats were daily treated with quercetin (30 mg/kg, for 5 weeks). At the end of the study, the imaging evaluation required to assess the effects of diabetes on carotid arteries was performed by micro-ultrasound (MU). The diabetic rats presented atherosclerotic plaques, with an increase in the echogenicity of the carotid artery wall, carotid intima-media thickness (CIMT), and carotid wall thickness, while the diabetic trained rats treated with quercetin presented normal values of these parameters. Malondialde-hyde (MDA) levels, superoxide dismutase (SOD) antioxidant enzyme activity, reduced glutathione (GSH) levels and the reduced (GSH) to oxidized (GSSG) glutathione ratio were determined in the carotid artery tissue. Diabetes caused elevated MDA levels and a decrease in SOD activity, GSH levels and GSH/GSSG ratio in the carotid artery tissue. Treating diabetic rats with quercetin combined with moderate exercise training reversed all these oxidative stress parameters. Our results show that this combination, quercetin and moderate exercise training, can be a good treatment strategy for the vascular complications of diabetes by attenuating hyperglycemia-mediated oxidative stress.

The Beneficial Effect of Swimming Training Associated with Quercetin Administration on the Endothelial Nitric Oxide-Dependent Relaxation in the Aorta of Rats with Experimentally Induced Type 1 Diabetes Mellitus

“…Quercetin has antioxidant effects in DM, scavenges the ROS, and also ensures anti-inflammatory and antiapoptotic protection participating in different protective mechanisms [ 36 , 39 ]. The results of the present study related to the quercetin properties in endothelial function recovery are concordant with recent literature data [ 4 , 6 , 36 , 39 ].…”

“…In the present study, the diabetic rats with moderate swimming training for 5 weeks showed significant decreased levels of FBG, in comparison with sedentary diabetic rats. These results are concordant to recent studies that presented the hypoglycaemic effects of moderate physical effort in diabetic rats [ 3 , 6 , 11 , 20 , 24 , 37 ]. The group of rats with DM and moderate swimming training treated with quercetin (DTQ group) showed a greater improvement of FBG levels, compared to the groups with only one approach: only training, or only quercetin treatment.…”

“…The endothelial dysfunction (ED) that occurs in type 1 diabetes mellitus (T1DM) involves numerous and diverse pathogenetic mechanisms including inflammation, hyperglycaemia, production of reactive oxygen species (ROS) and of reactive nitrogen species (RNS), the decrease of nitric oxide (NO) availability or dyslipidemia [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. Endothelial dysfunction is characterised by altered endothelial-dependent relaxation (EDR) produced by the decreased NO levels in the vessel wall [ 8 , 9 , 10 ], a process that leads to micro- and macrovascular complications, increasing significantly the morbidity and mortality in T1DM [ 1 ].…”

“…The moderate training physical effort enhances the insulin sensitivity and the carbohydrates metabolism in T1DM. Several recent studies made on T1DM presented the ameliorated endothelial dysfunction and the improved EDR after moderate exercise training that decreased the inflammation, the ROS/RNS production, and increased NO levels in vessel walls [ 4 , 6 , 11 , 12 , 13 , 14 ]. The type of the performed physical effort and its duration were correlated with the training efficacy in T1DM [ 11 ], the favourable effects in EDR enhancement and on the oxidative/nitrosative stress being recorded only after moderate exercise training [ 15 ] while the strenuous training intensified the ROS production [ 11 , 15 ].…”