Effect of gender on training-induced vascular remodeling in SHR

There is accumulating evidence that physical inactivity, associated with the modern sedentary lifestyle, is a major determinant of hypertension. It represents the most important modifiable risk factor for cardiovascular diseases, which are the leading cause of morbidity and mortality for both men and women. In addition to involving sympathetic overactivity that alters hemodynamic parameters, hypertension is accompanied by several abnormalities in the skeletal muscle circulation including vessel rarefaction and increased arteriole wall-to-lumen ratio, which contribute to increased total peripheral resistance. Low-intensity aerobic training is a promising tool for the prevention, treatment and control of high blood pressure, but its efficacy may differ between men and women and between male and female animals. This review focuses on peripheral training-induced adaptations that contribute to a blood pressure-lowering effect, with special attention to differential responses in male and female spontaneously hypertensive rats (SHR). Heart, diaphragm and skeletal muscle arterioles (but not kidney arterioles) undergo eutrophic outward remodeling in trained male SHR, which contributed to a reduction of peripheral resistance and to a pressure fall. In contrast, trained female SHR showed no change in arteriole wall-to-lumen ratio and no pressure fall. on the other hand, training-induced adaptive changes in capillaries and venules (increased density) were similar in male and female SHR, supporting a similar hyperemic response to exercise.

Exercise training prevents hyperinsulinemia, muscular glycogen loss and muscle atrophy induced by dexamethasone treatment

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of physical training with different intensities of effort on lipid metabolism in rats submitted to the neonatal application of alloxan

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Hipothalamy-pituitary axis: Effects of physical training in rats administered with dexamethasone

Aim. To investigate the effects of physical training associated to dexamethasone administration in carbohydrate metabolism and adrenocorticotrophic hormone (ACTH) release. Materials and methods. Young Wistar rats were divided into four groups: sedentary control (CS), sedentary dexanzethasone (DxS), trained control (CT) and trained dexamethasone (DxT). The rats were submitted to swimming training associate to administration of dexamethasone for ten weekends. Before sacrifice the rats received Subcutaneous insulin to calculate the maximum decreased in blood glucose. Venous blood was sampled obtained at the end experiment period to determine glucose, insulin, free fatty acids (FFA) and ACTH. Gastrocnemius and liver tissue samples were used to determination glycogen, and adipose epididimal tissue was used to measured the weight. Results. Dexamethasone administration provoke insulin resistance and the physical training reverted this aspect. Training promoted increase in muscle and liver glycogen store and a high utilization of FFA. Moreover the dexamethasone provoke decreased of ACTH release in response to acute exercise, showing marked differences in the functioning of the hypothalamy pituitary-adrenal (HPA) axis between groups of rats. Conclusions. a) Low-dose of dexamethasone promote several side effects in metabolism intermediary and chronic exposure to steroid was associated with insulin resistance; b) the regular swimming exercise promoted increased insulin sensitiviry Therefore. exercise can override the dexametasone negative feedback of the HPA axis activation in rats.

Is gender crucial for cardiovascular adjustments induced by exercise training in female spontaneously hypertensive rats?

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influência do treinamento resistido e do raloxifeno no metabolismo ósseo de ratas Wistar

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Exercise training decreases mitogen-activated protein kinase phosphatase-3 expression and suppresses hepatic gluconeogenesis in obese mice

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Exercise training as treatment in cancer cachexia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

High intensity exercise training worsens alveolar destruction in pulmonary emphysema rats

OBJECTIVE: Investigation of standard intensities of physical exercise is important to better comprehend and develop rehabilitation programs for emphysema. We aimed to evaluate the effects of different intensities (moderate and high-intensity) of physical exercise on the development of a protease-induced (papain intratracheal instillation) emphysema in rats. METHODS: Male Wistar rats were randomly separated into five groups that received intratracheal instillation of papain solution or vehicle: (i) papain high intensity exercise, (ii) papain moderate exercise, (iii) saline high intensity exercise, (iv) saline sedentary and (v) papain sedentary. Forty days after intratracheal instillation, the exercise groups were submitted to an exercise-training protocol on a treadmill during 10 weeks, 5 days/week, at 0.9 km/h (Papain and saline high exercise), or at 0.6 km/h (papain moderate exercise).We measured respiratory system elastance and resistance, the collagen fiber lung parenchyma, and the pulmonary mean linear intercept. RESULTS: All animal groups that received papain instillation presented higher alveolar wall destruction compared to animals that received only saline solution. The papain high intensity exercise group presented higher values of mean linear intercept compared to emphysema groups that were trained at a moderate intensity or not submitted to exercise. CONCLUSION: High intensity exercise training worsened alveolar destruction in an experimental model of emphysema in rats when compared to moderate intensity exercise, or to no exercise.

Analysis of autonomic modulation after an acute session of resistance exercise at different intensities in chronic obstructive pulmonary disease patients

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Exercício resistido no tratamento e prevenção de osteopenia de ratos machos jovens

Pós-graduação em Ciência Animal - FMVA

An experimental model for resistance exercise in rodents

This study aimed to develop an equipment and system of resistance exercise (RE), based on squat-type exercise for rodents, with control of training variables. We developed an operant conditioning system composed of sound, light and feeding devices that allowed optimized RE performance by the animal. With this system, it is not necessary to impose fasting or electric shock for the animal to perform the task proposed (muscle contraction). Furthermore, it is possible to perform muscle function tests in vivo within the context of the exercise proposed and control variables such as intensity, volume (sets and repetitions), and exercise session length, rest interval between sets and repetitions, and concentric strength. Based on the experiments conducted, we demonstrated that the model proposed is able to perform more specific control of other RE variables, especially rest interval between sets and repetitions, and encourages the animal to exercise through short-term energy restriction and "disturbing" stimulus that do not promote alterations in body weight. Therefore, despite experimental limitations, we believe that this RE apparatus is closer to the physiological context observed in humans.

Endurance exercise training increases APPL1 expression and improves insulin signaling in the hepatic tissue of diet-induced obese mice, independently of weight loss

Hepatic insulin resistance is the major contributor to fasting hyperglycemia in type 2 diabetes. The protein kinase Akt plays a central role in the suppression of gluconeogenesis involving forkhead box O1 (Foxo1) and peroxisome proliferator-activated receptor gamma co-activator 1 alpha (PGC-1a), and in the control of glycogen synthesis involving the glycogen synthase kinase beta (GSK3 beta) in the liver. It has been demonstrated that endosomal adaptor protein APPL1 interacts with Akt and blocks the association of Akt with its endogenous inhibitor, tribbles-related protein 3 (TRB3), improving the action of insulin in the liver. Here, we demonstrated that chronic exercise increased the basal levels and insulin-induced Akt serine phosphorylation in the liver of diet-induced obese mice. Endurance training was able to increase APPL1 expression and the interaction between APPL1 and Akt. Conversely, training reduced both TRB3 expression and TRB3 and Akt association. The positive effects of exercise on insulin action are reinforced by our findings that showed that trained mice presented an increase in Foxo1 phosphorylation and Foxo1/PGC-1a association, which was accompanied by a reduction in gluconeogenic gene expressions (PEPCK and G6Pase). Finally, exercised animals demonstrated increased at basal and insulin-induced GSK3 beta phosphorylation levels and glycogen content at 24?h after the last session of exercise. Our findings demonstrate that exercise increases insulin action, at least in part, through the enhancement of APPL1 and the reduction of TRB3 expression in the liver of obese mice, independently of weight loss. J. Cell. Physiol. 227: 29172926, 2012. (C) 2011 Wiley Periodicals, Inc.

Exercise training prevents diastolic dysfunction induced by metabolic syndrome in rats

OBJECTIVE: High fructose consumption contributes to the incidence of metabolic syndrome and, consequently, to cardiovascular outcomes. We investigated whether exercise training prevents high fructose diet-induced metabolic and cardiac morphofunctional alterations. METHODS: Wistar rats receiving fructose overload (F) in drinking water (100 g/l) were concomitantly trained on a treadmill (FT) for 10 weeks or kept sedentary. These rats were compared with a control group (C). Obesity was evaluated by the Lee index, and glycemia and insulin tolerance tests constituted the metabolic evaluation. Blood pressure was measured directly (Windaq, 2 kHz), and echocardiography was performed to determine left ventricular morphology and function. Statistical significance was determined by one-way ANOVA, with significance set at p<0.05. RESULTS: Fructose overload induced a metabolic syndrome state, as confirmed by insulin resistance (F: 3.6 +/- 0.2 vs. C: 4.5 +/- 0.2 mg/dl/min), hypertension (mean blood pressure, F: 118 +/- 3 vs. C: 104 +/- 4 mmHg) and obesity (F: 0.31 +/- 0.001 vs. C: 0.29 +/- 0.001 g/mm). Interestingly, fructose overload rats also exhibited diastolic dysfunction. Exercise training performed during the period of high fructose intake eliminated all of these derangements. The improvements in metabolic parameters were correlated with the maintenance of diastolic function. CONCLUSION: The role of exercise training in the prevention of metabolic and hemodynamic parameter alterations is of great importance in decreasing the cardiac morbidity and mortality related to metabolic syndrome.

Carbohydrate supplementation delays DNA damage in elite runners during intensive microcycle training

The aim of this study was to evaluate the effect of carbohydrate supplementation on free plasma DNA and conventional markers of training and tissue damage in long-distance runners undergoing an overload training program. Twenty-four male runners were randomly assigned to two groups (CHO group and control group). The participants were submitted to an overload training program (days 1-8), followed by a high-intensity intermittent running protocol (10 x 800 m) on day 9. The runners received maltodextrin solution (CHO group) or zero energy placebo solution as the control equivalent before, during, and after this protocol. After 8 days of intensive training, baseline LDH levels remained constant in the CHO group (before: 449.1 +/- 18.2, after: 474.3 +/- 22.8 U/L) and increased in the control group (from 413.5 +/- 23.0 to 501.8 +/- 24.1 U/L, p < 0.05). On day 9, LDH concentrations were lower in the CHO group (509.2 +/- 23.1 U/L) than in the control group (643.3 +/- 32.9 U/L, p < 0.01) post-intermittent running. Carbohydrate ingestion attenuated the increase of free plasma DNA post-intermittent running (48,240.3 +/- 5,431.8 alleles/mL) when compared to the control group (73,751.8 +/- 11,546.6 alleles/mL, p < 0.01). Leukocyte counts were lower in the CHO group than in the control group post-intermittent running (9.1 +/- 0.1 vs. 12.2 +/- 0.7 cells/mu L; p < 0.01) and at 80 min of recovery (10.6 +/- 0.1 vs. 13.9 +/- 1.1 cells/mu L; p < 0.01). Cortisol levels were positively correlated with free plasma DNA, leukocytes, and LDH (all r > 0.4 and p < 0.001). The results showed that ingestion of a carbohydrate beverage resulted in less DNA damage and attenuated the acute post-exercise inflammation response, providing better recovery during intense training.