Evidence that leucine improves structural and functional aspects of skeletal muscle regeneration (2013)
- USP affiliated authors: MORISCOT, ANSELMO SIGARI - ICB ; MIYABARA, ELEN HARUKA - ICB
- Unidade: ICB
- Subjects: ANATOMIA; RATOS; LEUCENA; SISTEMA MUSCULOESQUELETICO; REGENERAÇÃO (FENOMENOS BIOLÓGICOS); SUPLEMENTOS ALIMENTARES PARA ANIMAIS
- Language: Português
- Abstract: Introdução Mammalian skeletal muscle tissue has the ability to adapt to environmental conditions, including a remarkable capacity to regenerate after damage. Although the regeneration has been explored carefully at the structural and cellular levels, the identification of strategies to improve this process is on-going. Thus, nutritional strategies, including supplementation with essential amino acids (like leucine), modulate protein turnover in skeletal muscle. Objetivos This study aimed to investigate the effect of leucine supplementation on morphological, molecular and functional aspects of regenerating skeletal muscles from rats. Métodos This study was approved by the Ethics in Animal Research Committee of the Institute of Biomedical Sciences at the University of Sao Paulo (# 87/2011). Two month-old rats were randomly assigned into two groups: control (C, n=6) and supplemented with leucine (Leu, n=6). In both groups, the left soleus muscles were subjected to cryolesion and analyzed at 1, 3 and 10 days later. Leu was administered orally once a day at a dose of 1.35g/kg of body mass. At the end of each time point the left and right soleus were removed and weighed.Morphological features were evaluated in unfixed histological sections stained with Toluidine Blue. To assess the myofiber caliber, cross-sectional area (CSA) was measured. In damaged soleus, the CSA was obtained only from the myofibers with centralized nuclei. Proteins expressionwas evaluated by Western blot, and muscle contractile function by in vivo electrostimulation.Resultados The body weight from both groups was unaltered. Damaged soleus muscles from both groups showed an increase in their weights (30%) only on post-cryolesion day 1. On post-cryolesion day 10, soleus showed myofibers with a significant reduced CSA (53% vs. undamaged soleus). At the same time point, the damaged soleus from Leu group showed myofibers with larger caliber (40% vs. only damaged). Undamaged soleus analyzed on post-supplementation day 10 presented larger myofiber CSA (45% vs. C non-supplemented group). Damaged soleus from both groups displayed a lower strength after the 1st tetanic stimulus (50% and 58% vs. undamaged C and Leu, respectively). Damaged soleus from C group presented a greater decrease after the 2nd stimulus (42% vs. 1st contraction); however there was no fall in the strength after the 2nd tetanic stimulus on Leu group. In addition, the development of fatigue was measured over 10 consecutive stimuli. Soleus from C group displayed loss of strength along the stimulus (26% vs. 1st contraction). Leu group did not show alterations. The damaged soleus from both groups displayed a reduction in strength after the 1st stimulus (56% and 62% vs. undamaged C and Leu, respectively), and there was a drop at the consecutive stimulus (37% vs. 1st contraction only in C group). The damaged soleus from Leu group did not present a decrease in muscle strength over the stimulus. Leu supplementation was also effective in reducing the expression of ubiquitinated proteins on soleus at 3 and 10 days after damage, however it did not induce activation of some elements from PI3K/Akt/mTOR signalling pathway. Conclusão The results suggest that Leu improves myofiber caliber gain and strength recovery of regenerating soleus through an attenuation of protein ubiquitination.
- Título do periódico: Resumos
- Conference titles: Reunião Anual da Federação de Sociedades de Biologia Experimental (FeSBE)
ABNTPEREIRA, M. G.; CARLASSARA, E. D. O. C.; AOKI, M. S.; MORISCOT, Anselmo Sigari; MIYABARA, Elen Haqruka. Evidence that leucine improves structural and functional aspects of skeletal muscle regeneration. Anais.. Caxambu: FeSBE, 2013.
APAPereira, M. G., Carlassara, E. D. O. C., Aoki, M. S., Moriscot, A. S., & Miyabara, E. H. (2013). Evidence that leucine improves structural and functional aspects of skeletal muscle regeneration. In Resumos. Caxambu: FeSBE.
NLMPereira MG, Carlassara EDOC, Aoki MS, Moriscot AS, Miyabara EH. Evidence that leucine improves structural and functional aspects of skeletal muscle regeneration. Resumos. 2013 ;
VancouverPereira MG, Carlassara EDOC, Aoki MS, Moriscot AS, Miyabara EH. Evidence that leucine improves structural and functional aspects of skeletal muscle regeneration. Resumos. 2013 ;
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