Acute exercise induce endothelial nitric oxide synthase phosphorylation via Akt and AMP-activated protein kinase in aorta of rats: Role of reactive oxygen species

AbstractBackgroundAcute exercise increases reactive oxygen species (ROS) levels, including hydrogen peroxide (H2O2). H2O2 promotes endothelial nitric oxide synthase (eNOS) activation and phosphorylation in endothelial cells. With this in mind, the present study was designed to evaluate ex vivo eNOS phosphorylation in rat aortas incubated with H2O2 and to test this hypothesis in vivo in the aortas of rats submitted to acute exercise.MethodsFor ex vivo studies, six groups of aortic tissue were formed: control, H2O2, N-acetylcysteine (NAC), LY294002, compound C, and LY294002 plus compound C. While incubation with H2O2 increased Akt, AMPK and eNOS phosphorylation, pre-incubation with NAC strongly reduced the phosphorylation of these enzymes. For in vivo studies, male Wistar rats were divided into four groups: control, cont+NAC, exercise, and exer+NAC. After a 3h swimming session, animals were decapitated and aortas were excised for biochemical and immunoblotting analysis.ResultsAcute exercise increased superoxide levels and dichlorofluorescein (DCF) concentrations, and this increase was related to phosphorylation of Akt, AMPK and eNOS. On the other hand, use of NAC reduced superoxide levels and DCF concentration. Reduced superoxide levels and DCF in the exer+NAC group were associated with decreased Akt, AMPK and eNOS phosphorylation. These results appear to be connected with vascular function because VASP phosphorylation increased in acute exercise and decreased in exer+NAC.ConclusionOur results indicate that ROS induced by acute exercise play the important role of activating eNOS, a process apparently mediated by Akt and AMPK

Reversion of hepatic steatosis by exercise training in obese mice: The role of sterol regulatory element-binding protein-1c

Aim: The dysregulation of regulatory element-binding protein-1c (SREBP-1c) is associated with hepatic steatosis. However, effects of exercise on SREBP-1c protein level in liver have not been investigated. Thus, in this study we investigated if reversion of the hepatic steatosis-induced by exercise training is related with levels of SREBP-1c. Main methods: Mice were divided into two groups: control lean mice (CT), fed on standard rodent chow, and obese mice (HF), fed on a high-fat diet for 2 months. After this period obese mice were divided in two groups: obese mice and obese mice submitted to exercise (HF + EXE). The HF + EXE group performed a running program of 50 min per day, 5 days per week, for 8 weeks. Forty-eight hours after the last exercise session, biochemical, immunoblotting, histology and immunohistochemistry analyses were performed. Key findings: Livers of HF mice showed increased SREBP-1c, FAS (Fatty Acid Synthase), SCD1 (Stearoyl-CoA Desaturase1) and CPT1 (Carnitine Palmitoyl Transferase1) protein levels (3.4, 5.0, 2.6 and 2.9 times, respectively), though ACC (Acetyl-CoA Carboxilase) phosphorylation dropped 4.2 times. In livers of HF + EXE, levels of SREBP-1c, FAS, SCDI and CPTI decreased 2.1, 1.9, 1.8, and 2.7 times, respectively), while ACC phosphorylation increased 3.0 times. Lower SREBP-1c protein levels after exercise were confirmed also by immunohistochemistry. Total liver lipids content was higher in HF (2.2 times) when compared to CT, and exercise training reduced it significantly (1.7 times). Significance: Our study allows concluding that the reduction in SREBP-1c protein levels is associated with steatosis reversion induced by exercise training9111-12395401CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQsem informaçã

Endurance exercise training ameliorates insulin resistance and reticulum stress in adipose and hepatic tissue in obese rats

Obesity-induced endoplasmatic reticulum (ER) stress has been demonstrated to underlie the induction of obesity-induced JNK and NF-kappa B activation inflammatory responses, and generation of peripheral insulin resistance. On the other hand, exercise has been used as a crucial tool in obese and diabetic patients, and may reduce inflammatory pathway stimulation. However, the ability of exercise training to reverse endoplasmatic reticulum stress in adipose and hepatic tissue in obesity has not been investigated in the literature. Here, we demonstrate that exercise training ameliorates ER stress and insulin resistance in DIO-induced rats. Rats were fed with standard rodent chow (3,948 kcal kg(-1)) or high-fat diet (5,358 kcal kg(-1)) for 2 months. After that rats were submitted to swimming training (1 h per day, 5 days for week with 5% overload of the body weight for 8 weeks). Samples from epididymal fat and liver were obtained and western blot analysis was performed. Our results showed that swimming protocol reduces pro-inflammatory molecules (JNK, I kappa B and NF-kappa B) in adipose and hepatic tissues. in addition, exercise leads to reduction in ER stress, by reducing PERK and eIF2 alpha phosphorylation in these tissues. in parallel, an increase in insulin pathway signaling was observed, as confirmed by increases in IR, IRSs and Akt phosphorylation following exercise training in DIO rats. Thus, results suggest that exercise can reduce ER stress, improving insulin resistance in adipose and hepatic tissue.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Univ Extremo Catarinense, Lab Fisiol & Bioquim Exercicio, Programa Posgrad Ciencias Saude, BR-88806000 Criciuma, SC, BrazilUniversidade Federal de São Paulo, UNIFESP, Sch Phys Educ, Dept Biosci, Santos, SP, BrazilUniv São Paulo, Sch Phys Educ & Sport Ribeirao Preto, BR-14049 Ribeirao Preto, SP, BrazilUniv Estadual Campinas, UNICAMP, Fac Sci Appl, Limeira, SP, BrazilUniversidade Federal de São Paulo, UNIFESP, Sch Phys Educ, Dept Biosci, Santos, SP, BrazilWeb of Scienc

Endurance exercise training ameliorates insulin resistance and reticulum stress in adipose and hepatic tissue in obese rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Obesity-induced endoplasmatic reticulum (ER) stress has been demonstrated to underlie the induction of obesity-induced JNK and NF-kappa B activation inflammatory responses, and generation of peripheral insulin resistance. On the other hand, exercise has been used as a crucial tool in obese and diabetic patients, and may reduce inflammatory pathway stimulation. However, the ability of exercise training to reverse endoplasmatic reticulum stress in adipose and hepatic tissue in obesity has not been investigated in the literature. Here, we demonstrate that exercise training ameliorates ER stress and insulin resistance in DIO-induced rats. Rats were fed with standard rodent chow (3,948 kcal kg(-1)) or high-fat diet (5,358 kcal kg(-1)) for 2 months. After that rats were submitted to swimming training (1 h per day, 5 days for week with 5% overload of the body weight for 8 weeks). Samples from epididymal fat and liver were obtained and western blot analysis was performed. Our results showed that swimming protocol reduces pro-inflammatory molecules (JNK, I kappa B and NF-kappa B) in adipose and hepatic tissues. In addition, exercise leads to reduction in ER stress, by reducing PERK and eIF2 alpha phosphorylation in these tissues. In parallel, an increase in insulin pathway signaling was observed, as confirmed by increases in IR, IRSs and Akt phosphorylation following exercise training in DIO rats. Thus, results suggest that exercise can reduce ER stress, improving insulin resistance in adipose and hepatic tissue.111920152023Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq