title: Intrinsic laryngeal muscles are spared from myonecrosis in the mdx mouse model of Duchenne muscular dystrophy.
abstract: Intrinsic laryngeal muscles share many anatomical and physiological properties with extraocular muscles, which are unaffected in both Duchenne muscular dystrophy and mdx mice. We hypothesized that intrinsic laryngeal muscles are spared from myonecrosis in mdx mice and may serve as an additional tool to understand the mechanisms of muscle sparing in dystrophinopathy. Intrinsic laryngeal muscles and tibialis anterior (TA) muscle of adult and aged mdx and control C57Bl/10 mice were investigated. The percentage of central nucleated fibers, as a sign of muscle fibers that had undergone injury and regeneration, and myofiber labeling with Evans blue dye, as a marker of myofiber damage, were studied. Except for the cricothyroid muscle, none of the intrinsic laryngeal muscles from adult and old mdx mice showed signs of myofiber damage or Evans blue dye labeling, and all appeared to be normal. Central nucleation was readily visible in the TA of the same mdx mice. A significant increase in the percentage of central nucleated fibers was observed in adult cricothyroid muscle compared to the other intrinsic laryngeal muscles, which worsened with age. Thus, we have shown that the intrinsic laryngeal muscles are spared from the lack of dystrophin and may serve as a useful model to study the mechanisms of muscle sparing in dystrophinopathy.
authors.affiliation: Departamento de Anatomia, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo 13083-970, Brazil.
authors.forename: Maria Julia
authors.initials: MJ
authors.lastname: Marques
authors.forename: Renato
authors.initials: R
authors.lastname: Ferretti
authors.forename: Viviane Urbini
authors.initials: VU
authors.lastname: Vomero
authors.forename: Elaine
authors.initials: E
authors.lastname: Minatel
authors.forename: Humberto Santo
authors.initials: HS
authors.lastname: Neto
mesh_terms: D000375:Aging / Q000473:pathology; D000818:Animals; D002467:Cell Nucleus / Q000473:pathology; D004195:Disease Models, Animal; D018450:Disease Progression; D016189:Dystrophin / Q000172:deficiency; D005070:Evans Blue; D007821:Laryngeal Muscles / Q000473:pathology* / Q000503:physiopathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018101:Mice, Inbred mdx; D018485:Muscle Fibers, Skeletal / Q000378:metabolism / Q000473:pathology; D020388:Muscular Dystrophy, Duchenne / Q000473:pathology* / Q000503:physiopathology*; D009336:Necrosis / Q000235:genetics / Q000473:pathology* / Q000503:physiopathology*; D012038:Regeneration / Q000502:physiology
chemical_list: D016189:Dystrophin; D005070:Evans Blue