Adaptações na junção neuromuscular de ratos Wistar submetidos ao alongamento estático e exercício resistido: análises morfológicas, moleculares e funcionais
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2021-05-26
Autores
Jacob, Carolina dos Santos [UNESP]
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Universidade Estadual Paulista (Unesp)
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Este trabalho busca descrever as diversas adaptações no ventre muscular e na região pós-sináptica da junção neuromuscular (JNM) frente ao alongamento estático prévio e a sua combinação ou não com as diferentes modalidades de treinamento resistido. Foram utilizados 60 ratos Wistar machos com 60 dias de idade divididos em 6 grupos: Controle (C); Alongamento (AL); Escada Vertical (EV); Escada Vertical com Sobrecarga (EVS); Alongamento + Escada Vertical (AEV); Alongamento + Escada Vertical com Sobrecarga (AEVS). O protocolo de alongamento estático consistiu em aplicação manual de dorsiflexão até o limite da amplitude de movimento da articulação talocrural. No protocolo de treinamento resistido dos Grupos EV e AEV, foi utilizada uma escada vertical onde os animais realizaram 24 sessões de treinamento durante 8 semanas, cada sessão consistindo em 9 escaladas. Os Grupos EVS e AEVS realizaram o mesmo protocolo, porém com adição de sobrecarga progressiva. Foram obtidos dados funcionais de tempo, movimento e trabalho realizado em cada sessão, a massa corporal e muscular. Após a eutanásia dos animais, foram coletadas e processadas as amostras dos músculos sóleo e plantar para as técnicas de microscopia de luz, histoquímica e imunomarcação (α-bulgarotoxina). A análise funcional revelou redução do tempo para EV, EVS e AEV, de movimento para EV e AEV, e de trabalho em EVS≠EV e AEVS≠AEV. Houve diferença na massa corporal apenas entre AEV≠AEVS. O músculo sóleo apresentou diferença em sua massa entre C≠AEV e AL≠AEV, enquanto o músculo plantar entre C, AL≠AEV e EV≠AEV. A região pós-sináptica do sóleo revelou redução da área total e corada, bem como no perímetro total e corado em EV e AL, redução no número de clusters e fragmentação em AL e AEVS, enquanto a dispersão de AEVS apresentou maiores valores. No plantar, o aumento da área total e corada possui uma relação direta com o aumento da intensidade do exercício, onde EVS apresentou maior valor e, o alongamento prévio revelou ser um fator moderador. Concluímos que o treinamento em escada vertical e o tipo miofibrilar resultam em diferentes efeitos na atividade morfológica do tecido músculo-esquelético e na região pós-sináptica, onde as adaptações de trabalho e hipertrofia muscular são diretamente proporcionais a intensidade do exercício físico. O alongamento prévio a exercícios menos intensos resultou em adaptações semelhantes na JNM do sóleo causadas pelo treinamento com sobrecarga, enquanto o alongamento prévio em ambos os protocolos de escada vertical reduziu a área corada e total da região pós-sináptica do plantar.
This work describes the adaptations in the muscular belly and the postsynaptic region of the neuromuscular junction (NMJ) in the face of previous static stretching combined or not with the different types of resistance training. Sixty male Wistar rats aged 60 days were divided into 6 groups: Control (C); Stretching (S); Vertical Ladder (VL); Vertical Ladder with Load (VLL); Stretching + Vertical Ladder (SVL); Stretching + Vertical Ladder with Load (SVLL). The static stretching protocol consisted of manual application of dorsiflexion up to the limit of the range of motion of the talocrural joint. In the resistance training protocol of the EV and AEV Groups, a vertical ladder was used which the animals performed 24 sessions during 8 weeks, each session consisting of 9 climbs. The EVS and AEVS performed the same protocol with the addition of overload. Functional data of time, movement, and work performed in each session, body and muscle mass were obtained. After, the samples from the soleus and plantar muscle belly were collected and processed for the techniques of light microscopy, histochemistry, and immunostaining (α-bulgarotoxin). Functional analysis revealed decreased time for EV, EVS, and AEV. Decreased movement for EV and AEV; and work for EVS ≠ EV and AEVS ≠ AEV. There was a difference in body mass between AEV ≠ AEVS. The muscular mass of the soleus a difference between C ≠ AEV and AL ≠ AEV, while the plantar muscle there was a difference between C, AL ≠ AEV, and EV ≠ AEV. The postsynaptic region of the soleus showed a decrease in the total and stained area, as well as in the total and stained perimeter in EV and AL, decrease in the number of clusters and fragmentation in AL and AEVS, while the dispersion of AEVS showed higher values. In the plantar, the increase in the total and stained area has a direct relation to the increase in the intensity of the exercise, where EVS presented a higher value and, the previous stretching proved to be a moderating factor. We concluded the training in the vertical ladder results in different effects on the morphological activity of musculoskeletal tissue and in the postsynaptic region, where the adaptations of work and muscle hypertrophy are directly proportional to the intensity of physical exercise. Static stretching before less intense exercise resulted in similar adaptations in the soleus NMJ induced by overload training, while the previous stretching in both vertical ladder protocols decreased the stained and total area of the plantar postsynaptic region.
This work describes the adaptations in the muscular belly and the postsynaptic region of the neuromuscular junction (NMJ) in the face of previous static stretching combined or not with the different types of resistance training. Sixty male Wistar rats aged 60 days were divided into 6 groups: Control (C); Stretching (S); Vertical Ladder (VL); Vertical Ladder with Load (VLL); Stretching + Vertical Ladder (SVL); Stretching + Vertical Ladder with Load (SVLL). The static stretching protocol consisted of manual application of dorsiflexion up to the limit of the range of motion of the talocrural joint. In the resistance training protocol of the EV and AEV Groups, a vertical ladder was used which the animals performed 24 sessions during 8 weeks, each session consisting of 9 climbs. The EVS and AEVS performed the same protocol with the addition of overload. Functional data of time, movement, and work performed in each session, body and muscle mass were obtained. After, the samples from the soleus and plantar muscle belly were collected and processed for the techniques of light microscopy, histochemistry, and immunostaining (α-bulgarotoxin). Functional analysis revealed decreased time for EV, EVS, and AEV. Decreased movement for EV and AEV; and work for EVS ≠ EV and AEVS ≠ AEV. There was a difference in body mass between AEV ≠ AEVS. The muscular mass of the soleus a difference between C ≠ AEV and AL ≠ AEV, while the plantar muscle there was a difference between C, AL ≠ AEV, and EV ≠ AEV. The postsynaptic region of the soleus showed a decrease in the total and stained area, as well as in the total and stained perimeter in EV and AL, decrease in the number of clusters and fragmentation in AL and AEVS, while the dispersion of AEVS showed higher values. In the plantar, the increase in the total and stained area has a direct relation to the increase in the intensity of the exercise, where EVS presented a higher value and, the previous stretching proved to be a moderating factor. We concluded the training in the vertical ladder results in different effects on the morphological activity of musculoskeletal tissue and in the postsynaptic region, where the adaptations of work and muscle hypertrophy are directly proportional to the intensity of physical exercise. Static stretching before less intense exercise resulted in similar adaptations in the soleus NMJ induced by overload training, while the previous stretching in both vertical ladder protocols decreased the stained and total area of the plantar postsynaptic region.
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Palavras-chave
Junção neuromuscular, Fenda pós-sináptica, Alongamento estático, Escada vertical, Dimensão fractal, Neuromuscular junction, Postsynaptic cleft, Static stretching, Vertical ladder, Fractal dimension, Área de secção transversa, Treinamento resistido, Motor endplate, Cross-section area, Resistance training