Mechanisms of protection against myonecrosis in extraocular muscles of the mdx mice / Mecanismos de proteção a mionecrose nos musculos extra-oculares de camundongos distroficos mdx

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Duchenne muscular dystrophy is one of the most common hereditary diseases. Abnormal calcium ion handling renders dystrophic muscle fibers more susceptible to necrosis. In the mdx mice, extraocular muscles (EOM) are protected and do not undergo myonecrosis. We investigated whether this protection is related to an increased expression of calcium-binding proteins, which may protect against the elevated calcium levels seen in dystrophic fibers. The expression of SERCA1 and calsequestrin was examined in EOM and in non-spared limb, diaphragm and sternomastoid muscles of control and mdx mice using immunofluorescence and immunoblotting. Dystrophic EOM presented a significant increase in the proteins studied, and a significant increase in β-dystroglycan expression. These proteins were reduced in the non-spared mdx muscles. The were no changes in utrophin distribution. The increase of Ca2+-handling proteins in dystrophic EOM may permit a better maintenance of calcium homeostasis, with the consequent absence of myonecrosis. The results further support the concept that abnormal Ca2+-handling is involved in dystrophinopaties.

ASSUNTO(S)

duchenne muscular dystrophy necrose distrofia muscular de duchenne musculos extra-oculares necrosis camundongo mdx mdx mice extra-ocular muscles

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