Related Experiment Video
Updated: Apr 12, 2026
An In Vitro Adult Mouse Muscle-nerve Preparation for Studying the Firing Properties of Muscle Afferents
Published on: September 24, 2014
Intermittent stretching induces fibrosis in denervated rat muscle
Fernanda M Faturi1, Rúbia C Franco1, Davilene Gigo-Benato1
1Research Laboratory of Neurological Physiotherapy, Department of Physiotherapy, Federal University of São Carlos, São Carlos, São Paulo, Brazil.
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.
Related Concept Videos
01:22Muscle Stimulation Frequency
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...
01:29Relaxation of Skeletal Muscles
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open....