The effect of ß-hydroxy-ß-methylbutyrate (HMB) on the morphology of skeletal muscle after concurrent training

The aim of the present study was to investigate the effects of β-hydroxy-β-methylbutyrate (HMB) supplementation in association with concurrent training on morphological soleus muscle of rats. Wistar male rats were divided randomly into four groups: Control (C), Supplemented (S), Training (T) and Training + Supplemented (TS). Groups S and TS received 76mg/kg/day of HMB and the training groups (T and TS) were inserted into concurrent training program 3 times/week for 8 weeks. HMB had positive effects either on body composition of the animals or in type II muscle fibers. The concurrent exercise training was able in reducing the total fat mass as well as in increasing the diameter of muscle fibers. Our findings shows that HMB had an anti-catabolic effect with reference to the parameters of volume, weight and morphology of the soleus muscle, and there was a positive interaction between HMB supplementation and concurrent exercise training

Effects of 14 weeks resistance training on muscle tissue in Wistar rats / Efecto de 14 semanas de entrenamiento de resistencia en el tejido muscular de ratas Wistar

The objective of the present study was to analyze the effects of 14 weeks of resistance training on muscle tissue in Wistar rats. 20 male Wistar rats were used in the study; 10 allocated to the untrained group (Group 1) and 10 to the trained (Group 2). The physical training (PT) program consisted of four sets of ten water jumps, three times a week for 14 weeks. A progressive increase in load was applied from the14nd to the 42nd day. Following this, the animals were euthanized with an overdose of potassium chlorate (100 mg/kg) applied intraperitoneally. The ventral portion of the gastrocnemius muscle was removed for histological processing. The muscles were frozen in liquid nitrogen and cut into thicknesses of 5 µm using a rotative microtome. The sections were stained with hematoxylin-eosin for general analysis of the structure of muscles and analysis of the area of muscle fibers. The reaction with NADH-TR was utilized for differentiation between fast twitch (FT) and slow twitch (ST) fibers. The sections subjected to staining and histochemical reactions were observed in normal and polarized light and photomicrographed using a microscope (Zeiss®). The measurement of muscle fibers was performed using AxioVision software (Zeiss®). Statistical analysis was performed using the Student t test for analysis of the samples average. An average area of 5061.29 µm2 for Group 1 versus 5768.93 µm2 for Group 2 was observed. It can be concluded that 14 weeks of training with water jumps was effective in increasing muscle area. An increase in transverse area section (TAS) of ST and FT was also verified in the trained group.

El objetivo fue investigar los efectos de 14 semanas de entrenamiento de resistencia sobre el tejido muscular de ratas Wistar. Fueron utilizadas 20 ratas, 10 en el grupo sin entrenamiento (Grupo 1) y 10 con entrenamiento (Grupo 2). El programa de entrenamiento físico estaba compuesto de cuatro series con 10 saltos acuáticos, tres veces en la semana, durante 14 semanas. Un aumento progresivo de la carga fue aplicado desde el día 14 al día 42. Los animales fueron eutanasiados con clorhidrato de potasio (100 mg/kg) intraperitoneal. La parte ventral del músculo gastrocnemio fue removida para el análisis histológico. La musculatura fue congelada en nitrógeno líquido y cortada con 5 µm de espesor con micrótomo rotatorio. La coloración fue H-E para el análisis del músculo y área en las fibras musculares. La reacción com NADH-TR fue utilizada para la comparación entre las fibras rápidas (FR) y fibras lentas (FL). Las reacciones histoquímicass se observaron bajo microscópio de luz (Zeiss®) y sobre las microfotografias obtenidas se realizaron las mediciones con el programa Axio Vision (Zeiss®). El análisis estadístico se realizó con la prueba t de student para comparación de medias. Se observó una media de 5061,29 µm2 en el Grupo 1 y 5768,93 µm2 en Grupo 2. Es posible concluir que 14 semanas de programa de entrenamiento físico con 10 saltos acuáticos son capaces de aumentar el área del músculo. Un aumento del área transversal de las FR y FL fue observado en el grupo 2.

Análise morfológica do músculo gastrocnêmio medial de ratos submetidos a um protocolo de treinamento concorrente / Morphological analysis of muscle of rats submitted to a protocol of concurrent training / Análisis morfológica del músculo de ratones sometidos a un protocolo de entrenamiento concurrente

O objetivo do presente estudo foi analisar as alterações morfológicas do músculo gastrocnêmio medial (GM) de ratos Wistar submetidos a oito semanas de treinamento concorrente (TC). Foram utilizados quinze ratos Wistar machos, separados em três grupos com cinco animais: linha de base (LB), controle (C) e treinados (T). O TC consistiu na realização de um treinamento de resistência aeróbia em natação (TRA) e um treinamento de força (TF) na mesma sessão, três vezes por semana, durante oito semanas. Foi observado um aumento de 4,4 % na comparação entre as médias da área da secção transversa do GM dos animais dos grupos T (4905,5 ± 77,1µm²) e C (4699,9 ± 78,3µm²). Conclui-se que o treinamento concorrente foi eficaz em promover hipertrofia no GM de ratos Wistar.

The aim of this study was to analyze the morphophysiological changes of medial gastrocnemius muscle (GM) of Wistar rats underwent to eight weeks of concurrent training (TC). We used fifteen male Wistar rats divided into three groups with five animals each: baseline (LB), control (C) and trained (T). The TC consisted of aerobic endurance training in swimming (TRA) and a forced training (TF) in the same session, three times per week, for eight weeks. There was an increase of 4.4% in the comparison between average cross section area of the GM in animals of groups T (4905,5 ± 77,1µm²) and C (4699,9 ± 78,3 µm²). It is concluded that concurrent training was effective in causing hypertrophy in GM of rats.

El objetivo de este estudio fue analisar los cambios morfofisiológicos del músculo gaastrocnemio medial (GM) de ratones Wistar sometidos a ocho semanas de entrenamiento concurrente (TC). Se utilizó quince ratones Wistar divididos en tres grupos com cinco animales: línea de base (LB), control (C) y entrenado (T). El TC consistió en un entrenamiento de resistencia aerobia en natación (TRA) y en un entrenamiento de fuerza (TF) en la misma sesión, tres veces por semana, durante ocho semanas. Hubo um aumento de 4,4% en la comparación promedio entre el area de la sección transversal de los grupos de animales T (4905,5 ± 77,1 µm²) y C (4699,9 ± 78,3 µm²). Se concluye que el entrenamiento concurrente fue eficaz en la causa de la hipertrofia en el GM de ratones Wistar.

Morfologia e histoquímica do tecido muscular esquelético de ratos após estiramento / Morphological and histochemical skeletal muscle tissue of rats after stretch

A lesão muscular constitui parte integrante do processo de adaptação a certos tipos de treinamento físico. Em atletas altamente treinados, a lesão muscular, representa uma resposta capaz de acelerar o turnover protéico. O presente trabalho teve por finalidade avaliar a morfologia, e as características metabólicas e contráteis dos tipos de fibras musculares. Foram utilizados 10 ratos Wistar com peso corporal médio de 350g com idade de 70 dias. Os animais foram submetidos a um estímulo elétrico (tetania) e a um estímulo mecânico (estiramento). Após 48h os animais foram eutanasidos mediante uma dose de pentobarbital sódico. Fragmentos da cabeça medial do músculo gastrocnêmio foram imersas em N-Hexana a -70º Cortes (8 µm) obtidos em um micrótomo criostato, (–20ºC), foram corados pela HE e outros submetidos as reações NADH-TR e m ATPase, (pH 4,6 e 10,4). O padrão fascicular mostrou-se desorganizado. Ao lado de várias fibras com diferentes estágios de fagocitose, observou-se um intenso infiltrado plasmolinfocitarios, com elevado numero de macrófagos, células miosatélites e células mesenquimatosas, e áreas com ausência de células musculares. A atividade oxidativa revelou-se levemente aumentada em todos os tipos de fibras normais e muito diminuída nas fibras em fase de fagocitose. Conforme revelado pela reação m-ATPase, após pré-incubação alcalina e ácida, lesões foram observadas nas fibras de contração lenta (Tipo I) e nas de contração rápida (Tipo II). Assim, decorridas 48h após o estímulo de tetania e estiramento mecânico, a lesão de fibras acompanhada de processo de fagocitose e o infiltrado de células miosatélites, macrófagos e células mesenquimatosas, foram os eventos mais evidentes. Em nível do tipo de fibras, as lesões comprometeram ambos os tipos.

Muscular injury constitutes an integral part of the adaptation process to certain types of physical training. In highly trained athletes, muscular injury, or so it seems, represents a response capable of speeding up the protein turnover. The goal of the present work was to evaluate the degree of morphologic alteration, as well as the metabolic and contractile characteristics of types of muscle fibers. Ten Wistar rats were used with an average corporal weight of 350g. The animals were submitted to both an electrical stimulation (tetany) and a mechanical stimulation (stretching). After 48h the animals were euthanized by means of a dose of pentobarbital, followed by the removal of the medial head of the gastrocnemius muscle. The muscular samples were first immersed in N-Hexan at -70°C, and then placed in a microtome cryostat at -20°C, where transversal cuts (8 µm) at the longest axle of staple fibers were obtained. Some cuts were submitted to HE and others to the reactions for NADH-TR and mATPase, (pH 4.6 and 10.4). In addition to some staple fibers in different stages of phagocytosis, an intense infiltration was observed, with a large number of macrophages, mesenchyma and myosatellite type cells, and areas with an absence of muscular cells. The oxidative activity was seen to be slightly augmented in all types of normal fibers but significantly decreased in fibers in the phagocytosis phase. As revealed by the m ATPase reaction after the acid and alkaline pre-incubation phase, lesions were observed in the two types of fibers, slow and fast contraction (Type I e II). Thus, 48 hours after the tetany/stretching, the lesion of fibers followed by the phagocytosis process and the infiltration of myosatellite cells, macrophages and mesenchymal cells were the most observed events. Regarding the types of fibers, the lesion seems to compromise both types.

Análise da plasticidade muscular de ratos submetidos a um protocolo de treinamento físico concorrente / Plasticity analysis muscle in rats submitted to one concurrent physical training protocol

O objetivo do presente estudo foi analisar as adaptações morfofisiológicas das fibras do músculo sóleo de ratos machos submetidos a oito semanas de treinamento concorrente. Foram utilizados 15 ratos Wistar machos, divididos em três grupos, com cinco animais cada: linha de base (LB), controle (C) e treinado (T). O protocolo de treinamento foi realizado três vezes por semana, durante oito semanas e consistia em 30 minutos de natação (treinamento de resistência aeróbia) seguidos, após um minuto de intervalo passivo, de quatro séries de 10 saltos aquáticos (treinamento de força), com um minuto de intervalo passivo entre as séries. Pré treinamento, os animais foram submetidos a um teste de lactato mínimo (LM) para a determinação da sobrecarga correspondente ao treinamento de resistência aeróbia (TRA). Além disso, a sobrecarga utilizada no treinamento de força (TF) foi correspondente a 50% da massa corporal total (MCT) de cada animal. Para observação das alterações morfofisiológicas das fibras musculares, utilizou-se o método de marcação interativa por meio do programa AxioVision 4.8. Para testar a normalidade dos dados, foi utilizado o tesde de Shapiro-Wilk, sendo a normalidade não comprovada, optou-se pela utilização do teste não paramétrico de Kruskal-Wallis, seguido do pós-teste de Dunn (STATISTICA 7®). Após as análises, observou-se que as fibras musculares dos animais do grupo T apresentaram maior mediana (6483,4 µm2) quando comparadas com as fibras dos grupos LB (2690,3 µm2) e C (5911,6 µm2). Assim sendo, pode-se concluir que oito semanas de treinamento concorrente causam hipertrofia nas fibras do músculo sóleo de ratos Wistar.

The aim of this study was to analyze morphological and physiological adaptations of the soleus muscle fibers of rats underwent eight weeks of concurrent training. A total of 15 male Wistar rats were divided into three groups with five animals each: baseline (BL), control (C) and trained (T). Thetraining protocol was performed three times per week for eight weeks and consisted of 30 minutes of swimming (aerobic endurance training) followed, after a minute of passive interval, four sets of 10 jumps water (strength training), with passive one-minute intervals between sets. Pre training, the animals were subjected to a test lactate minimum (LM) to determine the overhead corresponding to aerobic endurance training (TRA). Furthermore, the overhead used for strength training (TF) is equal to 50% of the totalbody mass (TBM) for each animal. For observation of the morphological and physiological changes of muscle fibers, we used the method of marking using the interactive program AxioVision 4.8. To test the normality of the data was performed using the Shapiro-Wilk tesde being normalcy unproven, we chose to use the nonparametric Kruskal-Wallis test followed by Dunn's post-test (STATISTICA 7 ®). After analysis, it was observed that muscle fibers of group T showed higher median (6483.4 µm2) compared with the fibers of the groups LB (2690.3 µm2) and C (5911.6 µm2). Thus, it can be concluded that eight week of concurrent training cause hypertrophy in the fibers of the soleus muscle of male Wistar rats.