Exercise training improves relaxation response and SOD-1 expression in aortic and mesenteric rings from high caloric diet-fed rats

Abstract

BackgroundObesity has been associated with a variety of disease such as type II diabetes mellitus, arterial hypertension and atherosclerosis. Evidences have shown that exercise training promotes beneficial effects on these disorders, but the underlying mechanisms are not fully understood. The aim of this study was to investigate whether physical preconditioning prevents the deleterious effect of high caloric diet in vascular reactivity of rat aortic and mesenteric rings.MethodsMale Wistar rats were divided into sedentary (SD); trained (TR); sedentary diet (SDD) and trained diet (TRD) groups. Run training (RT) was performed in sessions of 60 min, 5 days/week for 12 weeks (70–80% VO2max). Triglycerides, glucose, insulin and nitrite/nitrate concentrations (NOx-) were measured. Concentration-response curves to acetylcholine (ACh) and sodium nitroprusside (SNP) were obtained. Expression of Cu/Zn superoxide dismutase (SOD-1) was assessed by Western blotting.ResultsHigh caloric diet increased triglycerides concentration (SDD: 216 ± 25 mg/dl) and exercise training restored to the baseline value (TRD: 89 ± 9 mg/dl). Physical preconditioning significantly reduced insulin levels in both groups (TR: 0.54 ± 0.1 and TRD: 1.24 ± 0.3 ng/ml) as compared to sedentary animals (SD: 0.87 ± 0.1 and SDD: 2.57 ± 0.3 ng/ml). On the other hand, glucose concentration was slightly increased by high caloric diet, and RT did not modify this parameter (SD: 126 ± 6; TR: 140 ± 8; SDD: 156 ± 8 and TRD 153 ± 9 mg/dl). Neither high caloric diet nor RT modified NOx- levels (SD: 27 ± 4; TR: 28 ± 6; SDD: 27 ± 3 and TRD: 30 ± 2 μM). Functional assays showed that high caloric diet impaired the relaxing response to ACh in mesenteric (about 13%), but not in aortic rings. RT improved the relaxing responses to ACh either in aortic (28%, for TR and 16%, to TRD groups) or mesenteric rings (10%, for TR and 17%, to TRD groups) that was accompanied by up-regulation of SOD-1 expression and reduction in triglycerides levels.ConclusionThe improvement in endothelial function by physical preconditioning in mesenteric and aortic arteries from high caloric fed-rats was directly related to an increase in NO bioavailability to the smooth muscle mostly due to SOD-1 up regulation.

Functional and Morphological Evaluation of the Mesenteric Artery, Kidney and Liver from Obese Rats: Impact of a High Fat Diet plus Fructose

“…These data suggest that the HFD+F induced vascular dysfunction which was not related to damage or disturbances in the smooth muscle intracellular response since endothelium independent relaxation was not affected by the treatment and morphological changes were not seen as well. This finding confirms previous studies that showed reduced endotheliumdependent relaxation without changes in the endothelium-independent relaxation in another model of rat obesity and other models of risk factors for cardiovascular disease such as arterial hypertension and diabetes [19][20][21][22]. Together with the morphological analysis of the mesenteric artery showing that the intima and medium layers were preserved in HFD+F group, it is suggestive that the impaired endothelium-dependent relaxation in the HFD+F group was not associated with damage in the endothelial layer.…”

Alterações vasculares em ratos obesos por dieta rica em gordura: papel da Via L-arginina/NO Endotelial

“…In addition, the obese rats developed metabolic disorders such as glucose intolerance, hyperinsulinemia and hyperleptinemia, characteristics commonly related to human obesity 15,19,20 . Insulin-resistance, defined as decreased sensitivity and/or responsiveness to metabolic actions of insulin, is a cardinal feature of diabetes, obesity and dyslipidemia 21 .…”

Efeito da dieta hiperlipídica e do treinamento aeróbico na aterosclerose em camundongos apoE-/-

“…Esse fato nos chamou a atenção, pois o grupo HT teve valores significativamente maiores no CT e LDL, menor valor na HDL e maior PRF. Com isso, sugere-se que o treinamento pode ter influenciado a formação e progressão da placa, pois estudos demonstraram que o exercício físico aeróbico melhora os sistemas de defesa orgânicos contra aterosclerose, diminuindo o estresse oxidativo e aumentando a síntese de enzimas antioxidantes, aumentando a vasodilatação dos vasos sanguíneos via óxido nítrico (NO) e óxido nítrico sintase endotelial (eNOS) e diminuindo a inflamação sistêmica pela diminuição da produção de citocinas pró-inflamatórias e aumento de fatores anti-inflamatórios [34][35][36] . Estudos têm sido feitos para a comprovação dos efeitos benéficos do exercício físico aeróbico na redução e prevenção de doenças cardiovasculares (DC) 2,34,37 .…”