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Intermittent stretching induces fibrosis in denervated rat muscle
Author(s) -
Faturi Fernanda M.,
Franco Rúbia C.,
GigoBenato Davilene,
Turi Andriette C.,
SilvaCouto Marcela A.,
Messa Sabrina P.,
Russo Thiago L.
Publication year - 2016
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.24702
Subject(s) - myostatin , fibrosis , denervation , connective tissue , muscle atrophy , atrophy , sarcomere , medicine , endocrinology , muscle hypertrophy , chemistry , anatomy , myocyte , muscle weakness , pathology
: 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. Muscle Nerve 53 : 118–126, 2016