Effect of ST36 electroacupuncture on the switch of skeletal muscle fibres in mice with sciatic nerve dissociation.

Skeletal muscle is striated muscle that moves autonomously and is innervated by peripheral nerves. Peripheral nerve injury is very common in clinical treatment. However, the commonly used treatment methods often focus on the regeneration of the injured nerve but overlook the pathological changes in the injured skeletal muscle. Acupuncture, as the main treatment for denervated skeletal muscle atrophy, is used extensively in clinical practice. In the present study, a mouse model of lower limb sciatic nerve detachment was constructed and treated with electroacupuncture Stomach 36 to observe the atrophy of lower limb skeletal muscle and changes in skeletal muscle fibre types before and after electroacupuncture Stomach 36 treatment. Mice with skeletal muscle denervation showed a decrease in the proportion of IIa muscle fibres and an increase in the proportion of IIb muscle fibres, after electroacupuncture Stomach 36. The changes were reversed by specific activators of p38 MAPK, which increased IIa myofibre ratio. The results suggest that electroacupuncture Stomach 36 can reverse the change of muscle fibre type from IIb to IIa after denervation of skeletal muscle by inhibiting p38 MAPK. The results provide an important theoretical basis for the treatment of clinical peripheral nerve injury diseases with electroacupuncture, in addition to novel insights that could facilitate the study of pathological changes of denervated skeletal muscle.

Evaluation of the comparative effects of infrared and red laser photobiomodulation therapy on skeletal muscle atrophy in an immobilization model in rats / Avaliação comparativa dos efeitos da terapia de fotobiomodulação com laser infravermelho e vermelho na atrofia muscular esquelética em modelo de imobilização em ratos

INTRODUCTION: Skeletal muscle atrophy leads to a reduction in muscle strength, functionality, and the quality of life of individuals. OBJECTIVE: To explore the effects of two different wavelengths (red and infrared) of laser PBMT on muscle atrophy and its active ingredients on skeletal muscle atrophy using an in vivo model of muscle atrophy. METHODS: Thirty-two Wistar rats were randomly divided into four experimental groups: control (CG) animals were not immobilized and did not receive any type of treatment; immobilized animals with no treatment (ImC); immobilized animals submitted to red laser with wavelength of 660 nm (ImR) and near-infrared laser with wavelength of 808 nm (ImIR) treatments. The treatments were applied daily, at 2 points in the right gastrocnemius muscle (cranial and caudal), through the punctual contact technique, for 9 sessions, with the first application immediately after removing the cast. RESULTS: The histological results demonstrated that in both treated groups (red and infrared wavelengths) a reduction of the inflammatory infiltrate and less connective tissue thickening when compared to the ImC. However, only infrared light was observed regenerating muscle fibers and an increase in the number of oxidative fibers (type I). CONCLUSION: These results suggest that red and infrared wavelength laser PBMT were able to promote changes in the morphology of the gastrocnemius muscle submitted to atrophy in an experimental immobilization model, reducing the inflammatory infiltrate and the formation of intramuscular connective tissue. However, infrared laser PBMT promoted more evident positive effects by increasing regenerating muscle fibers and the number of oxidative fibers.

Efeito da corrente alternada simétrica sinusoidal na musculatura estriada esquelética desnervada experimentalmente / Effect of sinusoidal alternated current in experimentally denerved skeletal striated muscle

Introdução: A utilização da estimulação elétrica (EE) no tratamento de músculos desnervados tem sido muito estudada, pois auxilia na reinervação tardia e minimiza a atrofia muscular. Objetivo: Neste estudo, avaliamos a EE através da corrente alternada simétrica sinusoidal na manutenção dos aspectos morfológicos dos músculos Extensor longo dos dedos (EDL) e Sóleo desnervados experimentalmente. Método: Quarenta ratos da linhagem wistar foram divididos em quatro grupos experimentais (n=10): Em grupo controle inicial (GCI), controle Final (GCF), desnervado (GD), e em desnervado e estimulado (GDE). A aplicação EE no músculo EDL e sóleo teve início 48 horas após a lesão nervosa, sendo aplicada três vezes por semana durante quarenta e cinco dias. Cortes transversais foram corados com HE para a mensuração da morfometria das fibras musculares. Para a análise estatística foi utilizado a análise de variância (one-way - ANOVA) seguido pelo teste de tukey (p < 0,05). Resultados: Os animais do grupo D e DE apresentaram uma diminuição da área de secção transversal (AST) quando comparadas ao CF. Porém o grupo DE minimizou a atrofia muscular, pois houve diferença estatisticamente significativa quando comparado ao D, tanto no músculo EDL quanto no sóleo. Conclusão: A EE foi eficiente na manutenção dos aspectos morfológicos dos músculos EDL e sóleo, minimizando a atrofia muscular. Podendo ser um tratamento útil para as lesões nervosas periféricas.

Introduction: the use of electrical stimulation (ES) in the treatment of denervated muscles has been studied as it assists in the late reinnervation and minimizes muscle atrophy. Purpose: this study assessed the ES through the symmetric sinusoidal alternating current in the maintenance of the morphological aspects of the experimentally denervated Extensor digitorum longus (EDL) and Soleus muscles. Method: Forty Wister rats were divided into four experimental groups (n = 10): initial control group ( ICG), final control group (FCG), denervated group (DG) and denervated and stimulated group (DSG). ES was first applied in the soleus and EDL muscle 48 hours after nerve injury, the applications took place three times per week for forty-five days. Cross-sections were stained with HE to perform the morphometric analysis of the muscle fibers. We used the analysis of variance (one-way - ANOVA) followed by the Tukey test (p < 0.05) for statistical analysis. Results: the animals belonging to group D and DE showed a decrease in the crosssectional area (CSA) when compared to FCG. However, the group DE had muscular atrophy minimized, as there was a statistically significant difference when compared to D, both for EDL and soleus muscles. Conclusion: the ES was effective in maintaining the morphological aspects of the EDL and soleus muscles, minimizing muscle atrophy. This may be a useful treatment for the peripheral nerve injuries.

Efeitos da estimulação elétrica neuromuscular durante a imobilização nas propriedades mecânicas do músculo esquelético / Efectos de la estimulación eléctrica neuromuscular durante la inmovilización en las propiedades mecánicas del músculo esquelético / Effects of neuromuscular electric stimulation during immobilization in the mechanical properties of the skeletal muscle

A estimulação elétrica neuromuscular (EENM) é um importante recurso utilizado em medicina esportiva para acelerar processos de recuperação. O objetivo deste estudo foi analisar os efeitos da EENM durante a imobilização do músculo gastrocnêmio, em posições de alongamento (LP) e encurtamento (SP). Para tanto, 60 ratas fêmeas jovens Wistar foram distribuídas em seis grupos e acompanhadas durante sete dias: controle (C), eletroestimuladas (EE), imobilizadas em encurtamento (ISP), imobilizadas em alongamento (ILP), imobilizadas em encurtamento e eletroestimuladas (ISP + EE) e imobilizadas em alongamento e eletroestimuladas (ILP + EE). Para a imobilização, o membro posterior direito foi envolvido por uma malha tubular e ataduras de algodão juntamente à atadura gessada. A EENM foi utilizada com freqüência de 50Hz, 10 minutos por dia, totalizando 20 contrações em cada sessão. Após sete dias os animais foram submetidos a eutanásia e os músculos gastrocnêmios retirados para a realização do ensaio mecânico de tração em uma máquina universal de ensaios (EMIC®). A partir dos gráficos carga versus alongamento, foram calculadas as seguintes propriedades mecânicas: alongamento no limite de proporcionalidade (ALP), carga no limite de proporcionalidade (CLP) e rigidez. As imobilizações SP e LP promoveram reduções significativas (p < 0,05) nas propriedades de ALP e CLP, sendo mais acentuada no grupo ISP. Quando utilizada a EENM, houve acréscimo significativo (p < 0,05) dessas propriedades somente no grupo ISP. Já em relação à rigidez, foi observada redução significativa (p < 0,05) somente do grupo C para o grupo ISP. Quando utilizada a EENM, a rigidez do grupo ILP + EE foi significativamente (p < 0,05) maior e mais próxima do grupo C que a do grupo ISP + EE. Neste modelo experimental, a imobilização dos músculos em alongamento atrasou o processo de atrofia, e a estimulação elétrica, realizada durante a imobilização, contribuiu para a manutenção das propriedades...

The neuromuscular electric stimulation (NMES) is an important tool used in sports medicine to accelerate the recovery process. The objective of this study was to analyze the effects of NMES during immobilization of the gastrocnemius muscle, in lengthened (LP) and shortened positions (SP). Sixty young female Wistar rats were distributed into six groups and followed for 7 days: control (C); electric stimulation (ES); immobilized in shortening (ISP); immobilized in lengthening (ILP); immobilized in shortening and electric stimulation (ISP + ES) and immobilized in lengthening and electric stimulation (ILP + ES). For the immobilization, a tubular mesh and cotton rolls together with the plaster were wrapped around the rat's right posterior paw. NMES in a frequency of 50 Hz was used 10 minutes a day, totaling 20 contractions in each session. After 7 days the animals were sacrificed and their gastrocnemius muscles of the right paw were submitted to a mechanical test of traction in a universal test machine (EMIC®). From the load versus elongation curves the following mechanical properties were obtained: elongation in the yield limit (EPL), load in the yield limit (LPL) and stiffness. The SP and LP immobilizations promoted significant reductions (p < 0.05) in the EPL and LPL properties, being more remarkable in the ISP group. When the NMES was used, there was significant increase (p < 0.05) of these properties only in the ISP group. As for stiffness, significant reduction was observed (p < 0.05) only of the C group for the ISP group. When the NMES was used, the stiffness of the ILP + EE group was significantly (p < 0.05) higher and closer to the C group than of the ISP + EE group. We conclude that in this experimental model the immobilization of the muscles in the lengthened position delayed the atrophy process and the electric stimulation during the immobilization contributed to the maintenance of the mechanical properties during the immobilization...

La estimulación eléctrica neuromuscular (EENM) es un importante recurso utilizado en medicina deportiva para acelerar procesos de recuperación. El objetivo de este estudio ha sido analizar los efectos de la EENM durante la inmovilización del músculo gastrocnemio, en posiciones de alongamiento (LP) y contracción (SP). Para tal fin, 60 ratones hembras jóvenes Wistar fueron distribuidas en seis grupos y monitoreadas durante 7 días: control (C), electro estimuladas (EE), inmovilizadas en contracción (ISP), inmovilizadas en alongamiento (ILP), inmovilizadas en contracción y electro estimuladas (ISP + EE) e inmovilizadas en alongamiento y electro estimuladas (ILP + EE). Para la inmovilización, el miembro posterior derecho fue envuelto por una malla tubular y vendas de algodón en conjunto con vendas de escayola. La EENM fue utilizada con una frecuencia de 50 Hz, 10 minutos por día, totalizando 20 contracciones en cada sesión. Después de 7 días los animales fueron sometidos a eutanasia y los músculos gastrocnemios fueron retirados para la realización del ensayo mecánico de tracción en una máquina universal de ensayos (EMIC®). A partir de los gráficos carga versus alongamiento se calculó las siguientes propiedades mecánicas: alongamiento en el límite de proporcionalidad (ALP), carga en el límite de proporcionalidad (CLP) y rigidez. Las inmovilizaciones SP y LP dieron reducciones significativas (p < 0,05) en las propiedades de ALP y CLP, siendo más acentuada en el grupo ISP. Cuando utilizamos la EENM, hubo un crecimiento significativo (p < 0,05) de estas propiedades solamente en el grupo ISP. Por otro lado, en relación a la rigidez, se observó una reducción significativa (p < 0,05) solamente del grupo C respecto al grupo ISP. También se observó que al usarse EENM, la rigidez del grupo ILP + EE fue significativamente (p < 0,05) mayor y más próxima del grupo C que la del grupo ISP + EE. En este modelo experimental, la inmovilización de los músculos...

Efectos de la suplementación con beta-hidroxi-beta-metilbutarato (HMB) sobre el daño muscular consecutivo a esfuerzo físico / Effects of HMB supplementation on muscle damage after exercise

Las exigencias físicas de ciertos tipos de deporte y pautas de entrenamiento plantean la necesidad de recurrir al uso de suplementos nutricionales que garanticen un adecuado recambio de aquellas sustancias sometidas a una alta tasa catabólica. El β-hidroxi -β-metilbutarato (HMB) ha demostrado poseer un efecto ergogénico sobre el rendimiento deportivo y prácticamente ningún efecto perjudicial sobre la salud del atleta. La suplementación con HMB pretende, en su aplicación más práctica y conociendo su poder anticatabólico, ayudar al deportista de alto nivel o al deportista poco entrenado a recuperar después de un ejercicio estresante obteniendo un grado de recuperación óptimo para emprender nuevas sesiones de actividad física y/o deportiva específica con el menor daño acumulado en su organismo (AU)

Most of the sport modalities and current training patterns demand high physiological, psycological, tecnical and tactical qualities from the athletes. There is a need for an optimal turnover of those substances with high catabolic rate. Several nutritional ergogenic aids can contribute to optimize these processes. In this sense, β-hydroxi- β-methylbutarate (HMB) has been proposed to have an ergogenic effect on athletic performance without having practically any adverse effect on the athlete’s health. This article reviews the literature about HMB in regard to mechanisms of action, effects on trained and non-trained subjects, optimal dose, and future research. In both highly-and low-trained subjects, HMB supplementation seems to contribute to a better recovery after hard training. This effect can contribute to decrease the accumulative effect on muscle damage caused by daily training sessions (AU)