Abstract
Denervation or inactivity is known to decrease the mass and alter the phenotype of muscle and the mechanics of tendon. It has been proposed that a shift in the collagen of the extracellular matrix (ECM) of the muscle, increasing type III and decreasing type I collagen, may be partially responsible for the observed changes. We directly investigated this hypothesis using quantitative real-time PCR on muscles and tendons that had been denervated for 5 wk. Five weeks of denervation resulted in a 2.91-fold increase in collagen concentration but no change in the content of collagen in the muscle, whereas in the tendon there was no change in either the concentration or content of collagen. The expression of collagen I, collagen III, and lysyl oxidase mRNA in the ECM of muscle decreased (76 ± 1.6%, 73 ± 2.3%, and 83 ± 3.2%, respectively) after 5 wk of denervation. Staining with picrosirius red confirmed the earlier observation of a change in staining color from red to green. Taken with the observed equivalent decreases in collagen I and III mRNA, this suggests that there was a change in orientation of the ECM of muscle becoming more aligned with the axis of the muscle fibers and no change in collagen type. The change in collagen orientation may serve to protect the smaller muscle fibers from damage by increasing the stiffness of the ECM and may partly explain why the region of the tendon closest to the muscle becomes stiffer after inactivity.
| Original language | English (US) |
|---|---|
| Journal | American Journal of Physiology - Regulatory Integrative and Comparative Physiology |
| Volume | 292 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 2007 |
| Externally published | Yes |
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Keywords
- Connective tissue
- Exercise
- Inactivity
- Injury
- Picrosirius red
ASJC Scopus subject areas
- Physiology
Cite this
Denervation does not change the ratio of collagen I and collagen III mRNA in the extracellular matrix of muscle. / Arruda, Ellen M.; Mundy, Kevin; Calve, Sarah; Baar, Keith.
In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 292, No. 2, 02.2007.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Denervation does not change the ratio of collagen I and collagen III mRNA in the extracellular matrix of muscle
AU - Arruda, Ellen M.
AU - Mundy, Kevin
AU - Calve, Sarah
AU - Baar, Keith
PY - 2007/2
Y1 - 2007/2
N2 - Denervation or inactivity is known to decrease the mass and alter the phenotype of muscle and the mechanics of tendon. It has been proposed that a shift in the collagen of the extracellular matrix (ECM) of the muscle, increasing type III and decreasing type I collagen, may be partially responsible for the observed changes. We directly investigated this hypothesis using quantitative real-time PCR on muscles and tendons that had been denervated for 5 wk. Five weeks of denervation resulted in a 2.91-fold increase in collagen concentration but no change in the content of collagen in the muscle, whereas in the tendon there was no change in either the concentration or content of collagen. The expression of collagen I, collagen III, and lysyl oxidase mRNA in the ECM of muscle decreased (76 ± 1.6%, 73 ± 2.3%, and 83 ± 3.2%, respectively) after 5 wk of denervation. Staining with picrosirius red confirmed the earlier observation of a change in staining color from red to green. Taken with the observed equivalent decreases in collagen I and III mRNA, this suggests that there was a change in orientation of the ECM of muscle becoming more aligned with the axis of the muscle fibers and no change in collagen type. The change in collagen orientation may serve to protect the smaller muscle fibers from damage by increasing the stiffness of the ECM and may partly explain why the region of the tendon closest to the muscle becomes stiffer after inactivity.
AB - Denervation or inactivity is known to decrease the mass and alter the phenotype of muscle and the mechanics of tendon. It has been proposed that a shift in the collagen of the extracellular matrix (ECM) of the muscle, increasing type III and decreasing type I collagen, may be partially responsible for the observed changes. We directly investigated this hypothesis using quantitative real-time PCR on muscles and tendons that had been denervated for 5 wk. Five weeks of denervation resulted in a 2.91-fold increase in collagen concentration but no change in the content of collagen in the muscle, whereas in the tendon there was no change in either the concentration or content of collagen. The expression of collagen I, collagen III, and lysyl oxidase mRNA in the ECM of muscle decreased (76 ± 1.6%, 73 ± 2.3%, and 83 ± 3.2%, respectively) after 5 wk of denervation. Staining with picrosirius red confirmed the earlier observation of a change in staining color from red to green. Taken with the observed equivalent decreases in collagen I and III mRNA, this suggests that there was a change in orientation of the ECM of muscle becoming more aligned with the axis of the muscle fibers and no change in collagen type. The change in collagen orientation may serve to protect the smaller muscle fibers from damage by increasing the stiffness of the ECM and may partly explain why the region of the tendon closest to the muscle becomes stiffer after inactivity.
KW - Connective tissue
KW - Exercise
KW - Inactivity
KW - Injury
KW - Picrosirius red
UR - http://www.scopus.com/inward/record.url?scp=33846846548&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33846846548&partnerID=8YFLogxK
U2 - 10.1152/ajpregu.00483.2006
DO - 10.1152/ajpregu.00483.2006
M3 - Article
C2 - 17008458
AN - SCOPUS:33846846548
VL - 292
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
SN - 1931-857X
IS - 2
ER -