Gilton de Jesus Gomes

Efeitos da suplementação de creatina e do treinamento de potência sobre a performance e a massa corporal magra de ratos

INTRODUCTION: Creatine is one of the supplements most used by athletes in order to increase protein synthesis and consequently muscle mass and strength. OBJECTIVE: This study investigated the effects of creatine intake on the performance and lean body mass of Wistar rats. METHODS: Male Wistar rats were allocated into one of the four groups: sedentary without creatine (S); Sedentary with creatine (SC); exercise without creatine (E); and exercise with creatine (EC) and received water and chow ad libitum. Those animals in SC and EC groups ingested creatine daily (0.430 g/kg body weight for 7 days and 0.070 g/kg body weight for the following 6 weeks). Animals from E and EC groups underwent a progressive vertical jump regimen (5 x 10 jumps with 1 min. resting interval) in a tank filled with water at 30 ± 1oC, 5 days/wk for 7 weeks. Performance was assessed by taking the time to perform 5 x 10 vertical jumps. The contents of water, fat and protein of the rats muscles and bones were measured. RESULTS: The performance was not affected by creatine intake (P > 0.05). Animals supplemented with creatine had an increased percentage of protein and a reduced percentage of fat (P 0.05). CONCLUSION: Creatine supplementation did not affect performance of the animals. Nevertheless, it altered the lean body mass. Creatine supplementation as well as the power training program, independently, raised the protein percentage of the muscles and bones and reduced the fat percentage, with no alteration in the water percentage.

Ventricular remodeling in growing rats with experimental diabetes: The impact of swimming training.

Diabetic cardiomyopathy is associated with cardiac muscle remodeling, resulting in myocardial dysfunction, whereas exercise training (ET) is a useful nonpharmacological strategy for the therapy of cardiac diseases. This study tested the effects of low-intensity swimming-training on the structural remodeling of the left ventricle (LV) in growing rats with unmanaged experimental diabetes. Thirty-day-old male Wistar rats were divided into four groups (n=5/group): sedentary-control (SC), exercised-control (EC), sedentary-diabetic (SD), and exercised-diabetic (ED). Swimming-training rats exercised 5 days/week, 90min/day, with a load of 5% BW during 8 weeks. Sections of LV were stained with Periodic acid-Schiff, Sirius Red, and Gomoris reticulin. Seven days and 8 weeks after streptozotocin (STZ) induction (60mgkg(-1) BW), blood glucose (BG) in the diabetic groups (SD=581.40±40.48; ED=558.00±48.89) was greater (p<0.05) than in their controls (SC=88.80±21.70; EC=85.60±11.55). Swimming-training reduced BG by 23mg/dL in the diabetics (p>0.05). The LV of diabetic rats had increased interstitial collagen and reticular fibers on the extracellular matrix and presented glycogen accumulation. More importantly, all these adverse tissue changes induced by STZ were attenuated by ET. Together, these findings support the idea of a beneficial role of exercise in the LV remodeling in rats with unmanaged type-1 diabetes mellitus.

Swimming training attenuates the morphological reorganization of the myocardium and local inflammation in the left ventricle of growing rats with untreated experimental diabetes.

Diabetic cardiomyopathy is associated with cardiac remodeling, myocardial dysfunction, low-grade inflammation, and reduced cardiac adiponectin in patients with type 1 diabetes mellitus (T1DM). Alternatively, physical exercise is an important strategy for the management of diabetes. This study aimed to investigate the influence of low-intensity swimming training in cardiac cytokines, structural remodeling, and cardiomyocyte contractile dysfunction in growing rats with untreated experimental DM. Thirty-day-old male Wistar rats were divided into four groups (n=14, per group): sedentary control (SC), exercised control (EC), sedentary diabetic (SD), and exercised diabetic (ED). Diabetes was induced by streptozotocin (60 mg kg(-1), i.p.). Animals from exercised groups swam (5 days/week, 90 min/day, loading up to 5% body weight around the animals chest) for 8 weeks. The left ventricle (LV) was removed for molecular, morphological, and cardiomyocyte mechanical analysis. Diabetic animals presented cardiac remodeling with myocardial histoarchitectural disorganization, fibrosis, and necrosis. The capillary density was lower in diabetic animals. LV cardiomyocytes from diabetic animals exhibited more prolonged time to the peak of contraction and time to half relaxation than those from control animals. The cardiac levels of interleukin 10, nitric oxide, and total and high molecular weight (HMW) adiponectin were significantly decreased in diabetic animals. Exercise training reduced the level of TNF-α, increased capillary density, and attenuated the histopathological parameters assessed in diabetic rats. In conclusion, the cardiac structural remodeling coexists with reduced levels of total and HMW adiponectin, inflammation, and cardiomyocyte contractility dysfunction in experimental DM. More important, low-intensity swimming training attenuates part of these pathological changes, indicating the beneficial role for exercise in untreated T1DM.

Attenuation of Ca2+ homeostasis, oxidative stress, and mitochondrial dysfunctions in diabetic rat heart: insulin therapy or aerobic exercise?

We tested the effects of swimming training and insulin therapy, either alone or in combination, on the intracellular calcium ([Ca(2+)]i) homeostasis, oxidative stress, and mitochondrial functions in diabetic rat hearts. Male Wistar rats were separated into control, diabetic, or diabetic plus insulin groups. Type 1 diabetes mellitus was induced by streptozotocin (STZ). Insulin-treated groups received 1 to 4 UI of insulin daily for 8 wk. Each group was divided into sedentary or exercised rats. Trained groups were submitted to swimming (90 min/day, 5 days/wk, 8 wk). [Ca(2+)]i transient in left ventricular myocytes (LVM), oxidative stress in LV tissue, and mitochondrial functions in the heart were assessed. Diabetes reduced the amplitude and prolonged the times to peak and to half decay of the [Ca(2+)]i transient in LVM, increased NADPH oxidase-4 (Nox-4) expression, decreased superoxide dismutase (SOD), and increased carbonyl protein contents in LV tissue. In isolated mitochondria, diabetes increased Ca(2+) uptake, susceptibility to permeability transition pore (MPTP) opening, uncoupling protein-2 (UCP-2) expression, and oxygen consumption but reduced H2O2 release. Swimming training corrected the time course of the [Ca(2+)]i transient, UCP-2 expression, and mitochondrial Ca(2+) uptake. Insulin replacement further normalized [Ca(2+)]i transient amplitude, Nox-4 expression, and carbonyl content. Alongside these benefits, the combination of both therapies restored the LV tissue SOD and mitochondrial O2 consumption, H2O2 release, and MPTP opening. In conclusion, the combination of swimming training with insulin replacement was more effective in attenuating intracellular Ca(2+) disruptions, oxidative stress, and mitochondrial dysfunctions in STZ-induced diabetic rat hearts.

SUPLEMENTAÇÃO COM ALTA DOSAGEM DE CAFEÍNA NÃO AFETA RESISTÊNCIA À FRATURA ÓSSEA EM RATAS SUBMETIDAS A TREINAMENTO DE SALTOS VERTICAIS

Objetivo: testar os efeitos de altas doses de cafeina na resistencia ossea a fratura em ratas jovens submetidas a treinamento de saltos verticais. Metodos: ratas jovens foram alocadas em 4 grupos (Fatorial 2 x 2, Cafeina e Exercicio). Grupos Cafeina receberam 3 doses (10 mg/100 g m.c.)/semana. Grupos Exercicio realizaram treino de saltos verticais na agua, 5 sessoes/semana, por 6 semanas. Avaliou-se o calcio urinario, diâmetro, massa e resistencia a fratura do femur. Resultados: cafeina e exercicio aumentaram a excrecao de calcio. Cafeina reduziu a massa femoral, mas nao afetou sua resistencia a fratura. Exercicio aumentou o diâmetro e a resistencia femoral a fratura. Conclusao: cafeina nao prejudica a resistencia ossea em ratas jovens enquanto saltos verticais fortalecem os ossos.

Supplementation with high dosage of caffeine do not affect bone breaking force in female rats submitted to a vertical jump training

Objetivo: testar os efeitos de altas doses de cafeina na resistencia ossea a fratura em ratas jovens submetidas a treinamento de saltos verticais. Metodos: ratas jovens foram alocadas em 4 grupos (Fatorial 2 x 2, Cafeina e Exercicio). Grupos Cafeina receberam 3 doses (10 mg/100 g m.c.)/semana. Grupos Exercicio realizaram treino de saltos verticais na agua, 5 sessoes/semana, por 6 semanas. Avaliou-se o calcio urinario, diâmetro, massa e resistencia a fratura do femur. Resultados: cafeina e exercicio aumentaram a excrecao de calcio. Cafeina reduziu a massa femoral, mas nao afetou sua resistencia a fratura. Exercicio aumentou o diâmetro e a resistencia femoral a fratura. Conclusao: cafeina nao prejudica a resistencia ossea em ratas jovens enquanto saltos verticais fortalecem os ossos.

Suplementación con alta cantidad de cafeína no afecta la resistencia sobre la fractura ósea en ratas sometidas al entrenamiento de saltos verticales

Objetivo: testar os efeitos de altas doses de cafeina na resistencia ossea a fratura em ratas jovens submetidas a treinamento de saltos verticais. Metodos: ratas jovens foram alocadas em 4 grupos (Fatorial 2 x 2, Cafeina e Exercicio). Grupos Cafeina receberam 3 doses (10 mg/100 g m.c.)/semana. Grupos Exercicio realizaram treino de saltos verticais na agua, 5 sessoes/semana, por 6 semanas. Avaliou-se o calcio urinario, diâmetro, massa e resistencia a fratura do femur. Resultados: cafeina e exercicio aumentaram a excrecao de calcio. Cafeina reduziu a massa femoral, mas nao afetou sua resistencia a fratura. Exercicio aumentou o diâmetro e a resistencia femoral a fratura. Conclusao: cafeina nao prejudica a resistencia ossea em ratas jovens enquanto saltos verticais fortalecem os ossos.