INTRODUCTION: Stretching (St) has been used for treating denervated muscles. However, its effectiveness and safety claims require further study. METHODS: Rats were divided into: (1) those with denervated (D) muscles, evaluated 7 or 15 days after sciatic nerve crush injury; (2) those with D muscles submitted to St during 7 or 15 days; and (3) those with normal muscles. Muscle fiber cross-sectional area, serial sarcomere number, sarcomere length, and connective tissue density were measured. MMP-2, MMP-9, TIMP-1, TGF-β1, and myostatin mRNAs were determined by real-time polymerase chain reaction. MMP-2 and MMP-9 activity was evaluated by zymography. Collagen I was localized using immunofluorescence. RESULTS: St did not prevent muscle atrophy due to denervation, but it increased fibrosis and collagen I deposition at day 15. St also upregulated MMP-9 and TGF-β1 gene expressions at day 7, and myostatin at day 15. CONCLUSIONS: Stretching denervated muscle does not prevent atrophy, but it increases fibrosis via temporal modulation of TGF-β1/myostatin and MMP-9 cascades.
INTRODUCTION: Stretching (St) has been used for treating denervated muscles. However, its effectiveness and safety claims require further study. METHODS:Rats were divided into: (1) those with denervated (D) muscles, evaluated 7 or 15 days after sciatic nerve crush injury; (2) those with D muscles submitted to St during 7 or 15 days; and (3) those with normal muscles. Muscle fiber cross-sectional area, serial sarcomere number, sarcomere length, and connective tissue density were measured. MMP-2, MMP-9, TIMP-1, TGF-β1, and myostatin mRNAs were determined by real-time polymerase chain reaction. MMP-2 and MMP-9 activity was evaluated by zymography. Collagen I was localized using immunofluorescence. RESULTS: St did not prevent muscle atrophy due to denervation, but it increased fibrosis and collagen I deposition at day 15. St also upregulated MMP-9 and TGF-β1 gene expressions at day 7, and myostatin at day 15. CONCLUSIONS: Stretching denervated muscle does not prevent atrophy, but it increases fibrosis via temporal modulation of TGF-β1/myostatin and MMP-9 cascades.
Authors: Júlia Araújo de Moura; Jaqueline de Morais; Samara Maria Neves Barbosa; Marcílio Coelho Ferreira; Ivo Vieira de Sousa Neto; Hércules Ribeiro Leite; Murilo Xavier Oliveira; Thaís Peixoto Gaiad; Ana Paula Santos Journal: J Exerc Rehabil Date: 2022-06-27
Authors: Sabrina M Peviani; Vinicius Guzzoni; Clara M Pinheiro-Dardis; Yara P da Silva; Alisson C R Fioravante; Adriana H Sagawa; Gabriel B Delfino; João L Q Durigan; Tania F Salvini Journal: Sci Rep Date: 2018-06-13 Impact factor: 4.379