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Isometric and Eccentric Force Generation Assessment of Skeletal Muscles Isolated from Murine Models of Muscular Dystrophies
Published on: January 31, 2013
Maximal force is unaffected by emphysema-induced atrophy in extensor digitorium longus
J P Mattson1, D C Poole, S A Hahn
1Department of Health and Exercise Science, Gustavus Adolphus College, 800 West College Avenue, St. Peter, MN 56082, USA. jmattson@gac.edu
Respiratory Physiology & Neurobiology
|March 4, 2008
Summary
Emphysema in hamsters caused muscle fiber atrophy but did not reduce maximal muscle force production. This suggests that despite muscle loss, exercise capacity may be maintained in chronic obstructive pulmonary disease (COPD).
Area of Science:
- Physiology
- Pulmonary Medicine
- Muscle Biology
Background:
- Chronic obstructive pulmonary disease (COPD) is associated with reduced exercise capacity.
- The role of muscle fiber atrophy and force production deficits in COPD-related functional limitations is not fully understood.
Purpose of the Study:
- To investigate if emphysema-induced muscle fiber atrophy leads to decreased locomotory muscle force production.
- To determine the relationship between muscle fiber size and force generation in an emphysema model.
Main Methods:
- Hamsters were induced with emphysema using elastase or saline (control).
- Maximal muscle force and muscle fiber cross-sectional area of the extensor digitorium longus were measured at 4 and 8 months post-instillation.
- Lung volume was assessed to confirm emphysema severity.
Main Results:
- Emphysema led to significant increases in lung volume at 4 and 8 months.
- While muscle mass and fiber cross-sectional area were reduced by 15% and 18% respectively at 8 months (P<0.01), maximal muscle force was preserved.
- No significant changes in muscle mass, force, or fiber cross-section were observed at 4 months.
Conclusions:
- Emphysema can induce significant muscle fiber atrophy in locomotory muscles.
- Maximal muscle force production can be maintained despite substantial muscle fiber atrophy in this emphysema model.
- These findings suggest that muscle atrophy may not be the sole determinant of exercise limitation in COPD.
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