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Updated: Jan 9, 2026
14:02
Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles
Published on: November 1, 2012
24.6K
Paraspinal muscle fibres demonstrate a complex relationship between contractile variability and function in canines
K Josh Briar1, Francesca Samarani2,3, Alex Chan3
1Department of Human Health Sciences, University of Guelph, Guelph, ON, Canada.
Scientific Reports
|December 2, 2025
Summary
Paraspinal muscle dysfunction in dogs with spinal issues shows greater fiber variability than in healthy rats. This highlights the importance of analyzing individual muscle fibers to understand spinal degeneration.
Area of Science:
- Biomedical Science
- Comparative Physiology
- Muscle Physiology
Background:
- Paraspinal muscle dysfunction is linked to spinal degeneration, but individual muscle fiber function remains poorly understood.
- Pathological changes in muscles can lead to significant variability in fiber capabilities.
Purpose of the Study:
- To investigate the variability in individual muscle fiber contractile function within paraspinal muscles.
- To compare fiber-level contractile function between chondrodystrophic canines and healthy rats.
Main Methods:
- Tested specific force, active modulus, and rate of force redevelopment (KTR) in individual muscle fibers from canine and rat paraspinal biopsies.
- Analyzed correlations between mean contractile performance and measures of absolute and relative variability (standard deviation, coefficient of variation).
Main Results:
- Canine muscle fibers exhibited greater relative variability and lower means compared to rat controls, indicating pathological impairment.
- Negative correlations were observed between contractile performance and relative variability, suggesting increased heterogeneity in impaired muscles.
- Two canines showed unusually high KTR in type 1 fibers, hinting at potential compensatory adaptations.
Conclusions:
- Altered within-muscle contractile function and increased fiber-level heterogeneity are characteristic of spinal pathology.
- Individual muscle fiber analysis is crucial for a comprehensive understanding of muscle dysfunction in spinal degeneration.
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