Force and power output of fast and slow skeletal muscles from mdx mice 6‐28 months old
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Discussion
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Implication
Animal study reveals persistent muscle hypertrophy alongside normalized force and power deficits in mdx mice, indicating that aging compounds functional weakness.
Key Points
- To determine how aging affects muscle mass, maximum isometric tetanic force, and power output in fast- and slow-twitch limb muscles of dystrophin-deficient mdx mice compared to control mice.
- Assessed extensor digitorum longus (EDL) and soleus muscles from mdx and control mice at 6, 17, 24, and 28 months of age.
- Measured maximum isometric tetanic force (Po) and power output in vitro at 25 °C, normalizing values to muscle cross-sectional area and muscle mass.
- EDL and soleus muscle masses in mdx mice were 9% to 42% larger than controls across all ages, remaining 17% and 22% heavier at 28 months.
- Muscle hypertrophy preserved absolute force and soleus power, but specific Po and normalized power were approximately 20% lower in mdx mice than controls across all ages.
- Normalized force and power decreased by approximately 28% with age in both strains, resulting in more severe weakness in aged mdx mice.
Cite This Study
Lynch et al. (2001) studied this question.