Transcriptional profile in rat muscle: down-regulation networks in acute strenuous exercise.

BACKGROUND: Physical exercise is a health promotion factor regulating gene expression and causing changes in phenotype, varying according to exercise type and intensity. Acute strenuous exercise in sedentary individuals appears to induce different transcriptional networks in response to stress caused by exercise. The objective of this research was to investigate the transcriptional profile of strenuous experimental exercise. METHODOLOGY: RNA-Seq was performed with Rattus norvegicus soleus muscle, submitted to strenuous physical exercise on a treadmill with an initial velocity of 0.5 km/h and increments of 0.2 km/h at every 3 min until animal exhaustion. Twenty four hours post-physical exercise, RNA-seq protocols were performed with coverage of 30 million reads per sample, 100 pb read length, paired-end, with a list of counts totaling 12816 genes. RESULTS: Eighty differentially expressed genes (61 down-regulated and 19 up-regulated) were obtained. Reactome and KEGG database searches revealed the most significant pathways, for down-regulated gene set, were: PI3K-Akt signaling pathway, RAF-MAP kinase, P2Y receptors and Signaling by Erbb2. Results suggest PI3K-AKT pathway inactivation by Hbegf, Fgf1 and Fgr3 receptor regulation, leading to inhibition of cell proliferation and increased apoptosis. Cell signaling transcription networks were found in transcriptome. Results suggest some metabolic pathways which indicate the conditioning situation of strenuous exercise induced genes encoding apoptotic and autophagy factors, indicating cellular stress. CONCLUSION: Down-regulated networks showed cell transduction and signaling pathways, with possible inhibition of cellular proliferation and cell degeneration. These findings reveal transitory and dynamic process in cell signaling transcription networks in skeletal muscle after acute strenuous exercise.

Test-retest reliability of electrical impedance myography in hamstrings of healthy young men.

Several techniques are available to assess muscle tissue status, including electrical impedance myography (EIM). Despite being used in the assessment of neuromuscular status in injury and response to exercise, reliability data for hamstrings muscles are limited. Therefore, this study aimed to determine the test-retest reliability of EIM components on hamstrings. Twenty-one healthy males (25.3 ± 3.4 years; 173 ± 6.7 cm; and 79.7 ± 15.9 kg) volunteered for this study. Subjects completed two visits, separated by seven days to collect EIM components (resistance, reactance, impedance, and phase angle) in the longitudinal and transversal axis of hamstrings in both thighs, using a bioimpedance device and Ag/AgCL adhesive contact electrodes. The electrode arrangement was in the muscular belly, half the distance between origin and insertion of the hamstrings. Reliability was determined by the intraclass correlation coefficient (ICC), minimal detectable change (MDC), and Bland-Altman plots. We observed high to excellent reliability (ICC > 0.85) between all EIM components, except for reactance with MDC ranged from 2.0 to 10.8 and the mean bias in Bland-Altman plots ranged from -0.02 to 2.48 (95% limits of agreement from -9.98 to 11.20). From our findings, the hamstrings assessment using EIM technique is reliable to assess muscle tissue; therefore, it enables the evaluation of changes/adaptations in clinical and applied contexts.

A compendium of physical exercise-related human genes: an 'omic scale analysis.

Regular exercise is an exogenous factor of gene regulation with numerous health benefits. The study aimed to evaluate human genes linked to physical exercise in an 'omic scale, addressing biological questions to the generated database. Three literature databases were searched with the terms 'exercise', 'fitness', 'physical activity', 'genetics' and 'gene expression'. For additional references, papers were scrutinized and a text-mining tool was used. Papers linking genes to exercise in humans through microarray, RNA-Seq, RT-PCR and genotyping studies were included. Genes were extracted from the collected literature, together with information on exercise protocol, experimental design, gender, age, number of individuals, analytical method, fold change and statistical data. The 'omic scale dataset was characterized and evaluated with bioinformatics tools searching for gene expression patterns, functional meaning and gene clusters. As a result, a physical exercise-related human gene compendium was created, with data from 58 scientific papers and 5.147 genes functionally correlated with 17 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. While 50.9% of the gene set was up-regulated, 41.9% was down-regulated. 743 up- and 530 down-regulated clusters were found, some connected by regulatory networks. To summarize, up- and down-regulation was encountered, with a wide genomic distribution of the gene set and up- and down-regulated clusters possibly assembled by functional gene evolution. Physical exercise elicits a widespread response in gene expression.

Effects of intermittent fasting and chronic swimming exercise on body composition and lipid metabolism.

Intermittent fasting protocol (IFP) has been suggested as a strategy to change body metabolism and improve health. The effects of IFP seem to be similar to aerobic exercise, having a hormetic adaptation according to intensity and frequency. However, the effects of combining both interventions are still unknown. Therefore, the aim of the present study was to evaluate the effects of IFP with and without endurance-exercise training on body composition, food behavior, and lipid metabolism. Twenty-week-old Wistar rats were kept under an inverted circadian cycle of 12 h with water ad libitum and assigned to 4 different groups: control group (ad libitum feeding and sedentary), exercise group (ad libitum feeding and endurance training), intermittent fasting group (IF; intermittent fasting and sedentary), and intermittent fasting and exercise group (IFEX; intermittent fasting and endurance training). After 6 weeks, the body weight of IF and IFEX animals decreased without changes in food consumption. Yet, the body composition between the 2 groups was different, with the IFEX animals containing higher total protein and lower total fat content than the IF animals. The IFEX group also showed increases in total high-density lipoprotein cholesterol and increased intramuscular lipid content. The amount of brown adipose tissue was higher in IF and IFEX groups; however, the IFEX group showed higher expression levels of uncoupling protein 1 in this tissue, indicating a greater thermogenesis. The IFP combined with endurance training is an efficient method for decreasing body mass and altering fat metabolism, without inflicting losses in protein content.

Use of murinometrics indices and bioelectrical impedance (BIA) in the determination of experimental obesity in oophorectomized rats / Uso de índices murinométricos e impedância bioelétrica (BIA) na determinação de obesidade experimental em ratas ooforectomizadas

In this study, we tested the use of murinometric indices and bioimpedance (BIA) to determine obesity in rats. Female Wistar rats (8 weeks/130-160 g) were divided into control and oophorectomy group. The Body Mass Index (BMI) and Lee index (LI) were used as anthropometric techniques to determine obesity, and the determination of body composition by BIA, as a way to partition body weight into fat mass and lean mass components. The dissection of muscle tissues and adipose deposits was used as a direct determination of body fat content. The groups had body weight gain (p <0.05) after the trial period, with a differential gain in body fat (p <0.05) observed by the dissection of tissue in the oophorectomy group. This gain in body fat was detected more accurately by BIA, due to the greater ability of this method to distinguish lean from fat mass. BIA was able to measure the differential gain of body fat in a BMI considered as eutrophic by murinometric indices.

Neste estudo, foi testado o uso de índices murinométricos e da bioimpedância (BIA) na determinação da obesidade em ratos. Ratas Wistar (8 semanas/130-160g) foram divididas em dois grupos: controle e ooforectomia. O Índice de Massa Corporal (IMC) e o índice de Lee (IL) foram utilizados como técnicas antropométricas para a determinação da obesidade e da composição corporal por BIA, como um meio de fracionamento do peso corporal em sua massa de gordura e componentes de massa magra. A dissecação dos tecidos musculares e depósitos adiposos foi utilizada como uma forma direta de determinação do teor de gordura corporal. Os grupos tiveram ganho de peso corporal (p <0,05) após o período experimental, com o grupo ooforectomia com ganho diferencial na gordura corporal (p <0,05), observada na dissecação do tecido adiposo. Esse ganho de gordura corporal foi percebido com maior precisão pela BIA devido à maior capacidade de diferenciação da massa corporal magra e da massa de gordura no peso corporal por meio do método. A BIA foi capaz de perceber o ganho diferencial da fração de gordura corporal em um IMC proposto como eutrófico pelos índices murinométricos.

A formação em saúde à luz do projeto pedagógico e das diretrizes curriculares da educação física / Health training under physical education’s pedagogical project and curricular guidelines / La capacitación en salud a la luz del proyecto pedagógico y de las directrices curriculares para la educación física

A Educação Física tem, tradicionalmente, se pautado em um conceito restrito de saúde. O objetivo deste trabalho é analisar no Projeto Pedagógico do Curso de Educação Física, bem como nas Diretrizes Curriculares Nacionais da área, o processo formativo ligado à atuação em saúde e ao SUS, por meio de pesquisa documental. Os pressupostos teóricos hegemônicos do curso e da área apresentam-se distantes dos princípios do SUS, reafirmando o alargamento entre as políticas de formação em Educação Física e as da Saúde Coletiva.

Traditionally, Physical Education has been based on a limited concept of health. Through document research, this work analyzes, in the Pedagogical Project of the Physical Education Course and the National Curriculum Guidelines for the area, the training process linked to working in health and at Brazil’s Unified Health System (SUS). The hegemonic theoretical assumptions of the course and the area are detached from SUS principles, underscoring the distance between educational policies in Physical Education and those in the public health field.

La Educación Física, tradicionalmente, se ha basado en un concepto limitado de salud. El objetivo de este trabajo es analizar el Proyecto Pedagógico del Curso de Educación Física, así como las Directrices Curriculares Nacionales de ese campo, el proceso de formación relacionado al desempeño en salud y al Sistema Único de Salud, SUS, mediante investigación documental. Las hipótesis teóricas hegemónicas del curso y del área se muestran distantes de los principios del SUS, reafirmando la brecha entre las políticas de formación en Educación Física y las de la salud colectiva.

Identificação de isoformas miosínicas estruturais de músculo gastrocnêmio de ratos treinados e sedentários em gel bidimensional / Identification of isoforms of myosin structural gastrocnemius muscle of trained rats and sedentary two-dimensional gel

A biologia molecular e a fisiologia humana fornecem ferramentas pelas quais a atividade física pode ser avaliada em termos de atuação e interação no organismo, induzindo adaptações estruturais e funcionais. Desta forma, as proteínas musculares podem ser usadas como eventuais marcadores moleculares. Neste trabalho caracterizou-se a expressão de isoformas miosínicas, através da obtenção de um mapa eletroforético bidimensional, em músculo esquelético de ratos, em decorrência da realização de exercícios em esteira adaptada. Ratos Wistar machos foram divididos aleatoriamente em dois grupos: sedentário e exercício, mantidos em condições ideais. O grupo exercício foi submetido a sessões de treinamento, em dias alternados, 30 minutos por dia, durante 12 semanas, utilizando velocidades de 7 m/min a 20 m/min. O padrão eletroforético bidimensional com faixa de pI ácido, apresentou vários grupos protéicos como as miosinas, tropomiosinas, troponinas e a actina, identificados in silico. Dentro desses grupos, foi verificada a presença de algumas isoformas leves de miosina e uma isoforma lenta de troponina T. Os géis proteômicos mostram-se importantes na análise da composição muscular. As isoformas protéicas, especialmente as miosínicas, podem ser úteis na caracterização do exercício em termos de expressão de proteínas além de poder contribuir na avaliação do exercício físico.

Molecular biology and human physiology providing tools by which physical activity can be assessed in terms of action and interaction in the body, inducing structural and functional changes. Thus, muscle proteins can be used as potential molecular markers. This study characterized the expression of myosin isoforms, by a two-dimensional electrophoretic map, in skeletal muscle of rats, as a result of induced exercise in treadmill. Wistar male rats were divided randomly into two groups: sedentary and exercise, held in ideal conditions. The exercise group was subjected to sessions of training on alternate days, 30 minutes per day for 12 weeks, using speed of 7 m / min to 20 m / min. The electrophoretic two-dimensional standard on acid pI range, presented various protein groups such as myosin, tropomyosin, troponin and actin, identified in silico. Within these groups, there was the presence of some light isoforms of myosin and a slow isoform of troponin T. The proteomic gels become important in analysis of the skeletal muscle composition. The protein isoforms, especially myosin, may be useful in characterizing the exercise training in terms of expression of proteins and could help in evaluation of the exercise.

Alterações morfométricas em músculo respiratório de ratos submetidos à imobilização de pata / Morphometric alterations in respiratory muscle of rats submitted to paw immobilization

A imobilização é um recurso frequentemente utilizado na prática clínica, sendo comum em patologias álgicas e nas fraturas. O objetivo deste estudo foi analisar a influência do processo de imobilização em músculo do sistema respiratório, o diafragma. O experimento foi efetuado com 12 ratos Wistar machos divididos em dois grupos, controle e imobilizado. O procedimento de imobilização foi realizado através de um método alternativo de imobilização por fita adesiva, sendo mantida por duas semanas. Analisou-se a morfometria das fibras do diafragma com coloração de hematoxilina e eosina. Ao compararmos o diâmetro médio das fibras musculares do diafragma dos animais imobilizados (47,15μm ± 0,329μm) em relação ao controle (54,67μm ± 0,396μm), encontramos diferença estatística entre os grupos (p < 0,0001). Considerando os dados encontrados, foi possível concluir que a imobilização de pata, no modelo utilizado, foi capaz de gerar hipotrofia da musculatura respiratória, assim como um quadro geral de redução de massa corporal do animal.

Immobilization is a frequently used procedure in clinical practice and common in pain diseases and fractures. This study examined the influence of immobilization in a muscle-related respiratory system, the diaphragm. This experiment was conducted with twelve male rats divided into two groups, control and immobilized with an alternative method of restraining by tape, kept for two weeks. We analyzed the morphometry of the diaphragm muscle fibers with hematoxylin/eosin staining. Statistical difference was found (p < 0.0001) when the average diameter of the diaphragm muscle fibers of immobilized animals (47.15μm ± 0.329μm) was compared to the ones in the control group (54.67μm ± 0.396μm). Considering the results, it can be concluded that the immobilization of the animal paw in the used model was able to produce hypotrophy of respiratory musculature, as well as a general framework for reducing the mass of the animal.