Extensor carpi ulnaris muscle shows unexpected slow-to-fast fiber-type switch in Duchenne muscular dystrophy dogs.
Dis Model Mech
; 14(12)2021 12 01.
Article
en En
| MEDLINE
| ID: mdl-34704592
ABSTRACT
Aged dystrophin-null canines are excellent models for studying experimental therapies for Duchenne muscular dystrophy, a lethal muscle disease caused by dystrophin deficiency. To establish the baseline, we studied the extensor carpi ulnaris (ECU) muscle in 15 terminal age (3-year-old) male affected dogs and 15 age/sex-matched normal dogs. Affected dogs showed histological and anatomical hallmarks of dystrophy, including muscle inflammation and fibrosis, myofiber size variation and centralized myonuclei, as well as a significant reduction of muscle weight, muscle-to-body weight ratio and muscle cross-sectional area. To rigorously characterize the contractile properties of the ECU muscle, we developed a novel in situ assay. Twitch and tetanic force, contraction and relaxation rate, and resistance to eccentric contraction-induced force loss were significantly decreased in affected dogs. Intriguingly, the time-to-peak tension and half-relaxation time were significantly shortened in affected dogs. Contractile kinetics predicted an unforeseen slow-to-fast myofiber-type switch, which we confirmed at the protein and transcript level. Our study establishes a foundation for studying long-term and late-stage therapeutic interventions in dystrophic canines. The unexpected myofiber-type switch highlights the complexity of muscle remodeling in dystrophic large mammals. This article has an associated First Person interview with the first author of the paper.
Palabras clave
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Distrofia Muscular de Duchenne
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Distrofia Muscular Animal
Tipo de estudio:
Prognostic_studies
Límite:
Aged
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Animals
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Humans
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Male
Idioma:
En
Revista:
Dis Model Mech
Asunto de la revista:
MEDICINA
Año:
2021
Tipo del documento:
Article
País de afiliación:
Estados Unidos