Protection from myonecrosis, and expression of SERCA1 and calsequestrin in dystrophic laryngeal muscles / Musculos laringeos distroficos : proteção a mionecrose, expressao de SERCA1 e calsequestrina

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Duchenne muscular dystrophy (DMD) and mdx mice, a model for DMD, is characterized by the lack of dystrophin expression and muscle fiber necrosis. Some muscle are enigmatically protected and admitted that an elevated expression of calcium-binding proteins. The intrinsic laryngeal muscles (ILMs) share many anatomical and physiological properties with extra-ocular muscles, which are unaffected in both Duchenne muscular dystrophy and mdx mice. We hypothesized that ILMs are spared from myonecrosis in the mdx and investigated whether this possible protection is related to an increased expression of calcium-binding proteins, SERCA1 and calsequestrin, which may be protective against the elevated calcium levels seen in dystrophic fibers. ILMs and limb muscles of adult and aged control C57Bl/10 and mdx mice were used. The percentage of central nucleated fibers, as a sign of muscle fibers that had experienced injury and regeneration, and myofibers labeling with Evans blue dye, as a marker of myofiber damage, were studied. After this characterization, the expression of Sarco-endoplasmic-reticulum Ca2+-ATPase (SERCA1) and calsequestrin was examined using immunofluorescence and immunoblotting. Except for the cricothyroid muscle (CT), none of the ILMs from adult and old mdx mice showed signs of myofiber damage. Central nucleation was readily visible in tibialis anterior of the same mdx mice. A significant increase in the percentage of central nucleated fibers was observed in adult CT compared to the other ILMs, which was worsened by age. Dystrophic ILMs presented a significant increase in the proteins studied, in comparison to controls. These proteins were reduced in the non-spared mdx muscles. Thus we show that the ILMs are spared from the lack of dystrophin and the increase of SERCA1 and calsequestrin may permit a better maintenance of calcium homeostasis with the consequent absence of myonecrosis.

ASSUNTO(S)

muscular dystrophy laryngeal muscles distrofia muscular serca1 musculos laringeos calsequestrin musculo esqueletico skeletal muscle calsequestrina

ACESSO AO ARTIGO

Documentos Relacionados