Botox Injections in Paraspinal Muscles Result in Low Maximal Specific Force and Shortening Velocity in Fast but Not Slow Skinned Muscle Fibers
| Autor: | Sang Kuy Han, Venus Joumaa, Walter Herzog, Keyoung Jin Chun, Kevin Boldt |
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| Rok vydání: | 2021 |
| Předmět: |
Male
medicine.medical_treatment Muscle Fibers Skeletal Paraspinal Muscles Myosin Back pain medicine Animals Humans Orthopedics and Sports Medicine Spasticity Botulinum Toxins Type A Saline Dystonia Specific force medicine.diagnostic_test business.industry Magnetic resonance imaging Anatomy medicine.disease Muscle atrophy Muscular Atrophy Neurology (clinical) Rabbits medicine.symptom business Muscle Contraction |
| Zdroj: | Spine. 47(11) |
| ISSN: | 1528-1159 |
| Popis: | Study design Basic science, experimental animal study. Objective To determine the effects of BTX-A injections on the mechanical properties of skinned muscle fibres (cells) of rabbit paraspinal muscles. Summary of background data Botulinum toxin type A (BTX-A) has been widely used in the treatment of disorders of muscle hyperactivity, such as spasticity, dystonia, and back pain. However, BTX-A injection has been shown to cause muscle atrophy, fat infiltration, and decreased force output in target muscles, but its potential effects on the contractile machinery and force production on the cellular level remain unknown. Methods Nineteen-month-old, male New Zealand White Rabbits received either saline or BTX-A injections into the paraspinal muscles, equally distributed along the left and right sides of the spine at T12, L1, and L2 at 0, 8, 12, 16, 20, and 24 weeks. Magnetic resonance imaging was used to quantify muscle cross-sectional area and structural changes before and at 28 weeks following the initial injection. Skinned fibres isolated from the paraspinal muscles were tested for their active and passive force-length relationships, unloaded shortening velocity and myosin heavy chain isoforms. Results BTX-A injections led to significant fat infiltration within the injected muscles and a greater proportion of IIa to IIx fibres. Isolated fast fibres from BTX-A injected animals had lower active force and unloaded shortening velocity compared to fibres from saline-injected control animals. Force and velocity properties were not different between groups for the slow fibres. Conclusion Injection of BTX-A into the paraspinal rabbit muscles leads to significant alterations in the contractile properties of fast, but not slow, fibres.Level of Evidence: N/A. |
| Databáze: | OpenAIRE |
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