Improvement of thoracic aortic vasoreactivity by continuous and intermittent exercise in high-fat diet-induced obese rats

Abstract

Abstract. The aim of the present study was to explore the effects of continuous and intermittent exercise on the thoracic aortic vasoreactivity and free radical metabolism in rats fed with a high-fat diet (HD). Sprague-Dawley (SD) rats were randomly divided into four groups (n=8, each group): Conventional diet (CD), HD, HD with continuous exercise (HCE) and HD with intermittent exercise (HIE). HCE rats swam once/day for 90 min; HIE rats performed swimming exercises 3 times/day, 30 min each time with an interval of 4 h. In these two groups, the exercise was conducted 5 days a week for 8 weeks. Rats in the CD and HD groups were fed without swimming training. At the end of the exercise, all the rats were sacrificed and the blood, thoracic aorta and myocardium were collected immediately. The thoracic aortic vasoreactivity, the plasma total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), superoxide dismutase (SOD), malondialdehyde (MDA) and vascular endothelial nitric oxide synthase (eNOS) gene expression were measured. Compared to the control group, in the HD group the enhanced contractile response of the thoracic aortic rings to noradrenaline (NA) was observed (P<0.01). The levels of TC and LDL (P<0.01) were also increased in serum while the HDL level was reduced without statistical significance. In addition, the MDA content was upregulated in the myocardium, but the SOD level decreased (P<0.01). Furthermore, the expression of vascular eNOS mRNA was reduced (P<0.01). However, following the exercise the contraction of the thoracic aorta vascular rings to NA was reduced in the HCE and HIE groups (P<0.01), and the decreased contractile response was more evident in the HIE group compared to the HCE group (P<0.01). Additionally, in the HCE group the level of TG (P<0.01) was decreased, while the HDL (P<0.01) level was increased. Although the reduction of the TC and LDL level was also observed there was no significant difference compared to the HD group. In the HIE group, the TG, TC and LDL were downregulated while the HDL was enhanced (P<0.01). The TC and LDL levels were decreased more than those of the HCE group; however, there was no significant difference in the TG and HDL levels between these two groups; additionally, in these two exercise groups, the MDA level was decreased in the myocardium (P<0.01) while the SOD level was increased (P<0.01). Furthermore, the expression of eNOS was upregulated (P<0.01), but the increase was much more in the HIE group than that in the HCE group. In conclusion, exercise may attenuate the aggravated contraction induced by NA and improve the activity of the thoracic aorta in obese rats, which may be associated with enhanced antioxidant enzyme activity and reduced free radical generating. Additionally, intermittent exercise is better than the continuous exercise in improving the thoracic aorta vasoreactivity.

Protective effect of naringin against ankylosing spondylitis via ossification, inflammation and oxidative stress in mice

“…Under normal physiological conditions, JAK2 mediates the signal transduction of a variety of cytokines, including erythropoietin, thrombopoietin, granulocyte-macrophage colony stimulating factor and IL-3, thus regulating and promoting cell proliferation (40). The present study showed that naringin also inhibited JAK2 protein expression in AS rat.…”

“…5). However, treatment with naringin (20,40 and 80 mg/kg) mitigated this increased expression of STAT3 protein in AS mouse (Fig. 5).…”

Pulmonary vascular dysfunction in metabolic syndrome

“…HF‐induced obese mice also exhibit enhanced agonist‐induced contraction in rat aorta (Liu et al . ), rat basilar artery (Lima et al . ) and mouse aorta (Mundy et al .…”

Disfunção mitocondrial no tecido adiposo perivascular e seu papel nas alterações vasculares em modelo experimental de obesidade

“…A disfunção vascular associada à obesidade tem sido amplamente discutida, sendo que o aumento na contração vascular pode ocorrer tanto pela ativação das vias de sinalização envolvidas na contração, quanto por prejuízos relacionados à ativação das vias de relaxamento. Indo ao encontro de trabalhos prévios (Naruse et al, 2006;Chinen et al, 2007;Liu et al, 2015), que mostram os prejuízos no sistema vascular causado pela obesidade, em nosso estudo observamos que a obesidade potencializa a contração vascular, e que tal resposta independe da presença do endotélio, indicando uma possível disfunção no MLV.…”

“…Para avaliação do perfil lipídico, foram determinados os níveis séricos de colesterol total, triglicerídeos e HDL (Lipoproteínas de alta densidade -High density lipoproteins), por métodos enzimáticos(Liu et al, 2015), em amostras de soros obtidas conforme descrito acima. A partir da concentração sérica de triglicerídeos, foram calculadas as concentrações de VLDL (Lipoproteínas de muito baixa densidade -Very low density lipoproteins), utilizando o seguinte cálculo: VLDL (mg/dL)= Triglicerídeos (mg/dL)/5.…”