Aerobic Exercise Training Prevents the Onset of Endothelial Dysfunction via Increased Nitric Oxide Bioavailability and Reduced Reactive Oxygen Species in an Experimental Model of Menopause

ObjectivePrevious studies have shown that estrogen deficiency, arising in postmenopause, promotes endothelial dysfunction. This study evaluated the effects of aerobic exercise training on endothelial dependent vasodilation of aorta in ovariectomized rats, specifically investigating the role of nitric oxide (NO) and reactive oxygen species (ROS).MethodsFemale Wistar rats ovariectomized (OVX - n= 20) or with intact ovary (SHAM - n= 20) remained sedentary (OVX and SHAM) or performed aerobic exercise training on a treadmill 5 times a week for a period of 8 weeks (OVX-TRA and SHAM-TRA). in the thoracic aorta the endothelium-dependent and - independent vasodilation was assessed by acetylcholine (ACh) and sodium nitroprusside (SNP), respectively. Certain aortic rings were incubated with L-NAME to assess the NO modulation on the ACh-induced vasodilation. the fluorescence to dihydroethidium in aortic slices and plasma nitrite/nitrate concentrations were measured to evaluate ROS and NO bioavailability, respectively.ResultsACh-induced vasodilation was reduced in OVX rats as compared SHAM (Rmax: SHAM: 86 +/-3.3 vs. OVX: 57+/-3.0%, p<0.01). Training prevented this response in OVX-TRA (Rmax: OVX-TRA: 88+/-2.0%, p<0.01), while did not change it in SHAM-TRA (Rmax: SHAM-TRA: 80+/-2.2%, p<0.01). the L-NAME incubation abolished the differences in ACh-induced relaxation among groups. SNP-induced vasodilation was not different among groups. OVX reduced nitrite/nitrate plasma concentrations and increased ROS in aortic slices, training as effective to restore these parameters to the SHAM levels.ConclusionsExercise training, even in estrogen deficiency conditions, is able to improve endothelial dependent vasodilation in rat aorta via enhanced NO bioavailability and reduced ROS levels.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Federal de São Paulo, Dept Biosci, São Paulo, BrazilUniv São Paulo, Inst Biomed Sci, Dept Physiol & Biophys, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biosci, São Paulo, BrazilFAPESP: 2012/17709-0FAPESP: 2010/50048-1Web of Scienc

Interaction between Advanced Glycation End Products Formation and Vascular Responses in Femoral and Coronary Arteries from Exercised Diabetic Rats

Background: The majority of studies have investigated the effect of exercise training (TR) on vascular responses in diabetic animals (DB), but none evaluated nitric oxide (NO) and advanced glycation end products (AGEs) formation associated with oxidant and antioxidant activities in femoral and coronary arteries from trained diabetic rats. Our hypothesis was that 8-week TR would alter AGEs levels in type 1 diabetic rats ameliorating vascular responsiveness. Methodology/Principal Findings: Male Wistar rats were divided into control sedentary (C/SD), sedentary diabetic (SD/DB), and trained diabetic (TR/DB). DB was induced by streptozotocin (i.p.: 60 mg/kg). TR was performed for 60 min per day, 5 days/week, during 8 weeks. Concentration-response curves to acetylcholine (ACh), sodium nitroprusside (SNP), phenylephrine (PHE) and tromboxane analog (U46619) were obtained. The protein expressions of eNOS, receptor for AGEs (RAGE), Cu/Zn-SOD and Mn-SOD were analyzed. Tissues NO production and reactive oxygen species (ROS) generation were evaluated. Plasma nitrate/nitrite (NOx-), superoxide dismutase (SOD), catalase (CAT), thiobarbituric acid reactive substances (TBARS) and N-epsilon-(carboxymethyl) lysine (CML, AGE biomarker). A rightward shift in the concentration-response curves to ACh was observed in femoral and coronary arteries from SD/DB that was accompanied by an increase in TBARS and CML levels. Decreased in the eNOS expression, tissues NO production and NOx- levels were associated with increased ROS generation. A positive interaction between the beneficial effect of TR on the relaxing responses to ACh and the reduction in TBARS and CML levels were observed without changing in antioxidant activities. The eNOS protein expression, tissues NO production and ROS generation were fully re-established in TR/DB, but plasma NOx- levels were partially restored. Conclusion: Shear stress induced by TR fully restores the eNOS/NO pathway in both preparations from non-treated diabetic rats, however, a massive production of AGEs still affecting relaxing responses possibly involving other endothelium-dependent vasodilator agents, mainly in coronary artery.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo-FAPESPFundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP

Effects of Exercise Training on Circulating and Skeletal Muscle Renin-Angiotensin System in Chronic Heart Failure Rats

Background: Accumulated evidence shows that the ACE-AngII-AT1 axis of the renin-angiotensin system (RAS) is markedly activated in chronic heart failure (CHF). Recent studies provide information that Angiotensin (Ang)-(1-7), a metabolite of AngII, counteracts the effects of AngII. However, this balance between AngII and Ang-(1-7) is still little understood in CHF. We investigated the effects of exercise training on circulating and skeletal muscle RAS in the ischemic model of CHF.Methods/Main Results: Male Wistar rats underwent left coronary artery ligation or a Sham operation. They were divided into four groups: 1) Sedentary Sham (Sham-S), 2) exercise-trained Sham (Sham-Ex), sedentary CHF (CHF-S), and exercise-trained CHF (CHF-Ex). Angiotensin concentrations and ACE and ACE2 activity in the circulation and skeletal muscle (soleus and plantaris) were quantified. Skeletal muscle ACE and ACE2 protein expression, and AT1, AT2, and Mas receptor gene expression were also evaluated. CHF reduced ACE2 serum activity. Exercise training restored ACE2 and reduced ACE activity in CHF. Exercise training reduced plasma AngII concentration in both Sham and CHF rats and increased the Ang-(1-7)/AngII ratio in CHF rats. CHF and exercise training did not change skeletal muscle ACE and ACE2 activity and protein expression. CHF increased AngII levels in both soleus and plantaris muscle, and exercise training normalized them. Exercise training increased Ang-(1-7) in the plantaris muscle of CHF rats. the AT1 receptor was only increased in the soleus muscle of CHF rats, and exercise training normalized it. Exercise training increased the expression of the Mas receptor in the soleus muscle of both exercise-trained groups, and normalized it in plantaris muscle.Conclusions: Exercise training causes a shift in RAS towards the Ang-(1-7)-Mas axis in skeletal muscle, which can be influenced by skeletal muscle metabolic characteristics. the changes in RAS circulation do not necessarily reflect the changes occurring in the RAS of skeletal muscle.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundacao ZerbiniCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Univ São Paulo, Sch Med, Heart Inst InCor HCFMUSP, São Paulo, BrazilUniv São Paulo, Sch Phys Educ & Sport, São Paulo, BrazilUniv São Paulo, Inst Biomed Sci, Dept Physiol & Biophys, São Paulo, BrazilUniversidade Federal de São Paulo, Kidney & Hypertens Hosp, Div Nephrol, São Paulo, BrazilUniversidade Federal de São Paulo, Kidney & Hypertens Hosp, Div Nephrol, São Paulo, BrazilFAPESP: FAPESP-2010/50048-1Web of Scienc

Time-dependent characterization of vascular reactivity in aorta of <font face=\"symbol\">a2A and <font face=\"symbol\">a2C-adrenoceptors knockout mice.

Este estudo avaliou a função vascular em anéis de aorta e no leito vascular mesentérico (LVM) de camundongos com deleção dos receptores a2A e a2Cadrenérgicos (KO) com 3, 5 e 7 meses, os quais apresentam uma hiperatividade simpática acompanhada de cardiomiopatia. Os KO apresentaram um aumento da freqüência cardíaca em todos os grupos avaliados, e hipertrofia ventricular esquerda aos 5 e 7 meses. Na aorta, o relaxamento dependente (acetilcolina) e independente (nitroprussiato de sódio) do endotélio e da via font face=\"symbol\">a-adrenérgica (isoproterenol), assim como a contração (fenilefrina e serotonina) e a mobilização de Ca2+ não foram alterados nos KO aos 3, 5 e 7 meses. Nos KO aos 3 meses, o relaxamento mediado pelos receptores ?2-adrenérgicos (clonidina) foi reduzido. Tanto a contração (noradrenalina) como o relaxamento (acetilcolina) no LVM dos KO aos 7 meses não foi alterado. Assim, sugere-se que os vasos arteriais parecem ser menos sensíveis do que o coração aos efeitos crônicos da hiperatividade simpática nos camundongos com deleção dos receptores a2A e a2C adrenérgicos.This study assed the vascular function in aortic rings and in mesenteric vascular bed (MVB) from mice with disruption of a2A and a2Cadrenoceptors (KO) with 3, 5 and 7 months of age, that present sympathetic hyperactivity associated with cardiomyopathy. Heart rate was increased in all KO groups, and left ventricular hypertrophy was observed only in 5 and 7 month-old KO. There are no changes in the relaxation induced by acetylcholine (ACh), sodium nitroprusside and isoproterenol in aortic rings from all groups. In addition, the contraction induced by phenylephrine and serotonin, and Ca2+ handling did not change. However, in aorta from 3 month-old KO the relaxation induced by clonidine (a2-adrenergic agonist) was reduced. In MVB from 7 month-old KO, neither the contraction (noradrenaline) nor relaxation (ACh) was modified. The results suggest that arterial vessel has been more resistant than heart to chronic effects induced by sympathetic hyperactivity observed in mice with disruption oa2A and a2C-adrenoceptors

Vascular resistance function in myocardial infarction rats.

Esta tese avaliou a função em artérias de resistência do músculo esquelético (ARME) e em coronárias septais (CS) de ratos com disfunção ventricular esquerda leve (LDV) e severa (SDV) pós-infarto do miocárdio (IM). As ARME e as CS foram montadas em miógrafo de arame. O relaxamento dependente do endotélio, mediado pela acetilcolina (ACh), foi reduzido nas ARME dos SDV e preservado nos LDV. A resposta à ACh foi reduzida na CS dos SDV e aumentada nos LDV. O relaxamento mediado pelo doador de óxido nítrico (NO) foi preservado em todas as artérias. Utilizando-se a sonda DAF-2 em cortes de CS, antes e após estimulação com ACh, detectou-se menor produção de NO nos SDV e maior produção de NO nos LDV. Na CS observou-se aumento das espécies reativas de oxigênio nos SDV e redução destas nos LDV. Detectou-se maior expressão protéica da sintase de NO endotelial e neuronal e das isoformas da superóxido dismutase na CS dos LDV em relação ao SHAM. Conclui-se que a função nas ARME e nas CS é modulada diferentemente na dependência do estado da função cardíaca pós-IM.This study assessed the reactivity in skeletal muscle resistance arteries (SMRA) and in septal coronary arteries (SC) from rats with slight (sliLVD) and severe (sevLVD) left ventricular dysfunction after myocardial infarction (MI). SMRA and the SC were mounted on a wire myograph. The endothelium-dependent relaxation by acetylcholine (ACh) was reduced in SMRA from sevLVD; but it was preserved in sliLVD. The ACh-relaxation was reduced in SC from sevLVD; while it was increased in sliLVD. The nitric oxide (NO) donor relaxation was unchanged in all arteries. Using DAF-2 probe in SC, before and after ACh stimulation, it was observed NO production decreased in SC from sevLVD, while it was increased in sliLVD. Reactive oxygen species was increased in SC from sevLVD and it was reduced in sliLVD. Neuronal and endothelial NO synthase and superoxide dismutase isoforms protein expression were greater in SC from sliLVD as compared to SHAM. In conclusion, SMRA and SC function is differentially modulated on the dependency of the cardiac function after MI

Protein expression of endothelial nitric oxide synthase (eNOS) and receptor for advanced glycation end products (RAGE).

<p>Protein expression of endothelial nitric oxide synthase (eNOS, panels A and B) and receptor for advanced glycation end products (RAGE, panels C and D) from isolated rats femoral and coronary arteries, respectively. Bottom panel representative Western Blot and top panel quantitative analysis. Data are mean ± SEM. The number of animals per group is indicated in the bars. *p<0.05 compared to C/SD and ⁺p<0.05 compared to SD/DB. Negative control (NC).</p

Plasma nitrate/nitrite (NO_x⁻), superoxide dismutase activity (SOD), catalase activity (CAT), <i>thiobarbituric acid reactive substances</i> (TBARS) and N^ε-(carboxymethyl) lysine (CML) in rats from control sedentary (C/SD); sedentary diabetic (SD/DB) and trained diabetic (TR/DB).

<p>Data are mean ± SEM. The number of animals per group is indicated in the parentheses.</p>*<p>p<0.05 compared to C/SD;</p>+<p>p<0.05 compared to SD/DB.</p

Concentration-response curves to contractile agents.

<p>Concentration-response curves to phenylephrine (PHE, panels A and B) and tromboxane mimetic 9,11-dideoxy-11α,9α-epoxy methanoprostaglandin F_2α (U46619, panels C and D) in rats femoral and coronary arteries, respectively, with intact endothelium from control sedentary (C/SD), sedentary diabetic (SD/DB) and trained diabetic (TR/DB). Maximal response values are inserted in the figure. Data are mean ± SEM. The number of animals per group is indicated in the figure.</p

Femoral and coronary artery diameters.

<p>Potency values (pEC₅₀) obtained from concentration-response curves to acetylcholine (ACh), sodium nitroprusside (SNP), phenylephrine (PHE) and tromboxane mimetic 9,11-dideoxy-11α,9α-epoxy methanoprostaglandin F_2α (U46619) in rats femoral and coronary arteries with intact endothelium from control sedentary (C/SD); sedentary diabetic (SD/DB) and trained diabetic (TR/DB).</p><p>Potency is represented as -log of molar concentration to produce 50% of the maximal responses. Data are mean ± SEM. The number of animals per group is indicated in the parentheses.</p>*<p>p<0.05 compared to C/SD;</p>+<p>p<0.05 compared to SD/DB.</p

Blood glucose, insulin tolerance test, water and food intake.

<p>Blood glucose (panel A), Insulin tolerance test (Kitt, panel B) water (panel C) and food (panel D) intake. Data are mean ± SEM. The number of animals per group is indicated in the figure. *p<0.05 compared to C/SD; ⁺p<0.05 compared to SD/DB.</p