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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Electrical Stimulation Based on Chronaxie Increases Fibrosis and Modulates TWEAK/Fn14, TGF-beta/Myostatin, and MMP Pathways in Denervated Muscles

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Author(s):
Pinheiro-Dardis, Clara Maria ; Russo, Thiago Luiz
Total Authors: 2
Document type: Journal article
Source: AMERICAN JOURNAL OF PHYSICAL MEDICINE & REHABILITATION; v. 96, n. 4, p. 260-267, APR 2017.
Web of Science Citations: 2
Abstract

Objective: The aim of this work was to investigate the effects of electrical stimulation (ES) of denervated muscles of rat in neuromuscular performance, muscle atrophy, and fibrosis formation. Design: Wistar rats were divided into normal (N), 7- or 15-day denervation (D7d and D15d), D7d or D15d plus ES (DES7d and DES15d, respectively). Sciatic nerves were crushed causing muscle denervation. Two hundred muscle contractions were electrically induced daily by surface electrodes, considering muscle chronaxie. Sciatic functional index was used to determine neuromuscular performance during walking. The muscle fiber cross-sectional area and percentage of connective tissue were assessed by light microscopy. Molecular markers of extracellular matrix production and remodeling were evaluated. Metalloproteinase (MMP) activity was assessed by zymography, and TWEAK, Fn14, myostatin, and transforming growth factor (TGF)-beta gene expressions were determined by real-time PCR. Results: Electrical stimulation impaired natural recovery of walking at 15 days. In addition, ES induced fibrosis and accentuated muscle atrophy in denervated muscles. Although ES reduced the accumulation of TWEAK and myostatin expressions, it up-regulated Fn14 and TGF-beta in a time-dependent manner. Electrical stimulation also increased the activity of MMP-2 compared to the other groups (P < 0.05). Conclusions: Electrical stimulation applied to denervated muscles induced muscle fibrosis and atrophy, as well as loss of performance. The TWEAK/Fn14 system, TGF-beta/myostatin pathway, and MMP activity seem to be involved in these deleterious changes. (AU)

FAPESP's process: 13/21621-3 - Effect of task specific training on muscle adaptation in gerbils post-ischemic stroke
Grantee:Thiago Luiz de Russo
Support Opportunities: Regular Research Grants