Pulmonary arterial hypertension (PAH) induced by monocrotaline (MCT) is an experimental protocol of right heart failure. We analyzed the role of exercise training on the right ventricle structure and function, pulmonary artery remodeling, and GSK-3β expression. Rats were divided among the following groups: sedentary control (SC), sedentary monocrotaline (SM), trained control (TC), and trained monocrotaline (TM). Rats underwent exercise training for a period of 5 weeks, with 3 weeks post-MCT injection. Rats in the SM and TM groups presented with an increase in right ventricle hypertrophy indexes and lung congestion. The right ventricular end diastolic pressure (RVEDP), right ventricular systolic pressure (RVSP), and its minimum and maximal pressure derivates were increased in the SM and TM groups. The right ventricle interstitial volume pulmonary artery thickness and p-GSK-3β/GSK-3β were increased in the MCT groups as compared with the control groups. The TM group had a reduction in interstitial volume, p-GSK-3β/GSK-3β ratio, pulmonary artery thickness, RVEDP, and an increase in intramyocardial vessels volume as compared with the SM group. The overall results have shown that the exercise protocol used promoted positive changes in right ventricle and pulmonary artery remodeling. These observations also suggest that structural remodeling may be influenced by signaling proteins, such as GSK-3β.

RESUMOO treinamento de força (TF) -também denominado treinamento com pesos -refere-se a um método especializado de condicionamento físico que envolve o uso progressivo de cargas resistivas desenvolvidas para aumentar ou manter a aptidão muscular. Atualmente o número de jovens engajados em programas de treinamento que incluem o TF está crescendo de forma vertiginosa. Tendo isso em vista, o objetivo dessa presente revisão é relatar os principais aspectos relacionados à segurança e à eficácia do TF em crianças e jovens e apresentar linhas de orientação desenvolvidas especificamente para essa população. O método utilizado foi uma revisão sistemática com a localização de artigos publicados entre 1993 e 2001 nas bases de dados PubMed, Scielo e Scopus. As evidências científicas encontradas nos estudos analisados indicam que o TF é saudável e apresenta diversos benefícios para crianças e adolescentes quando esses são instruídos, apropriadamente, por instrutores qualificados que se baseiam em linhas de orientação corretas de treino. Assim sendo, o TF pode ser praticado por crianças, pois se apresenta de forma segura e benéfica à saúde dessa população. Palavras-Chave:Treinamento de força; Crianças; Jovens; Linhas de orientação; Lesão. YOUTH STRENGTH TRAINING: SAFETY, BENEFITS AND GUIDELINES ABSTRACTStrength training (ST) -also named as weight training -refers to a specialized method of physical training that involves the progressive use of resistive loads developed to increase or maintain the physical fitness. Nowadays the number of youth engaged in physical programs that includes the ST is increasing quickly. In view of that, the aim of this review is report the main aspects related to youth ST safety, efficacy, and guidelines developed especially for this sort of population. The used method was a systematic review with papers published between 1993 and 2011, in PubMed, Scielo and Scopus. The scientific evidence found in the assessed studies indicates that ST is health and has many benefits for children and adolescents when these are instructed properly by qualified instructors who are based on proper guidelines training. Thus, the ST can be practiced by youth, as it is safe and beneficial to the health of this sort of population.

Pulmonary arterial hypertension (PAH) is a disease that increases the pulmonary vascular resistance, causing hypertrophy and subsequent right heart failure. Oxidative stress is involved in the pathogenesis of PAH, and estrogen is considered an antioxidant. Thus, the aim of this study was to test the hypothesis that estrogen could attenuate PAH by modulating oxidative stress. Female Wistar rats were ovariectomized or suffered the surgery simulation (sham). After 7 days, subcutaneous pellets with 17β-estradiol or sunflower oil were implanted. At this time, PAH was induced by means of a single dose of monocrotaline (MCT) (60 mg·kg(-1) i.p.). The experimental groups were as follows: (1) sham, (2) sham + MCT, (3) ovariectomy (O), (4) ovariectomy + MCT (OM), (5) ovariectomy + estrogen replacement + MCT (ORM). Hemodynamic measurements were performed 21 days after MCT or saline. Nonovariectomized animals were assessed in the stage of diestrus. Afterwards, the rats were killed to collect the heart, the lung and the liver to evaluate morphometry. Samples of the right ventricle were used to analyse the reduced glutathione : oxidized glutathione ratio. Lung congestion in the OM group, which was decreased in the ORM group, was observed. Right ventricle end-diastolic pressure was increased in the OM and the ORM groups. The glutathione ratio decreased in the groups O, OM and ORM. The data suggest that estrogen can exert great influence on the cellular redox balance. The maintenance of physiological estrogen levels may help to avoid the appearance of pulmonary oedema, characteristic of this model of PAH, and right ventricular failure.

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Fonte de auxílio à pesquisa:trabalho não financiado.Conflitos de interesse: os autores declaram que não há conflitos de interesses.