Estudo de proteínas relacionadas ao costâmero em secções longitudinais de músculo sóleo de ratas imobilizadas e reabilitadas pelo alongamento passivo manual intermitente / Study of costameric proteins in soleus muscle longitudinal sections of female rats immobilized and rehabilitated by intermittent passive manual stretching

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

04/06/2012

RESUMO

The interface between sarcolemma and extracellular matrix in skeletal muscle tissue is constituted by specialized proteins that are responsible for the transversal and longitudinal forces transmission to the myofiber. Skeletal muscle adaptations to physiological and pathological forces, such as segmental immobilization and rehabilitation exercises, may contribute to cellular perception of mechanical signals and consequently induce alterations related to flexibility and muscular force. This study investigated the tissue responses of the soleus muscle in female rats caused by longitudinal stress induced by the association of passive stretching training with the free movement after immobilization of the right hind limb. The right hind limbs of female rats were immobilized during 10 days in a plantar flexion in order to keep the soleus muscle in a shortened position. After the immobilization, the animals were submitted to intermittent passive manual stretching. The animals gait was functionally analyzed before immobilization and during the period of stretching or free movement. Ninety-six adult female Wistar rats were divided into 8 groups: Immobilized (I); Immobilized and stretched for 1 day (IS(1)); Immobilized and stretched for 3 days (IS(3)); Immobilized and stretched for 10 days (IS(10)); Immobilized and free for 1 day (IF(1)); Immobilized and free for 3 days (IF(3)); Immobilized and free for 10 days (IF(10)); Immobilized control (C(Immob)). After the experimental period, the soleus muscle was removed, frozen and further processed by Hematoxylin-eosin stain; immunohistochemistry reactions for fibronectin, types I and III collagen; imunofluorescence of laminin, dystrophin and macrophages; western blot of dystrophin and laminin. Qualitative and quantitative results were obtained using a Light Microscope and a system of image analysis. The between- and within-group data were analyzed using Mixed-Effects Linear Models. After the immobilization, the animals presented loss of body weight and alterations in size and shape of the fibers. Furthermore, the hypokinesia changed the functional variables of gait, reduced the dorsiflexion range of motion (ROM), increased the intracellular fibronectin/total number of fibers ratio (FIF/TNFr), the expression of dystrophin, of laminin and of the types I and III collagen. After three days of remobilization, the morphological changes were exacerbated: intense cellularity, nuclear centralization, inclusion bodies and necrosis. These findings showed increased in the IS(3). The groups IS(3) and IF(3) also showed functional impairment, ROM restriction, increased FIF/TNFr and immunoreactivity of the type III collagen. Others findings observed in these groups were increase of the amount of macrophages in the tissue and of dystrophin. The abnormalities related to gait parameters and the morphological changes induced by immobilization were improved in the IS(10) group. The remobilization using stretching for ten days showed significant effectiveness and reverted the skeletal muscle abnormalities induced by disuse, especially concerning the functional variables.

ASSUNTO(S)

alongamento terapêutico análise funcional da marcha functional analysis of gait immobilization imobilização morfologia morphology músculo sóleo ratas rats soleus muscle. therapeutic stretching

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