ABSTRACT
Extracellular matrix and costamere proteins transmit the concentric, isometric, and eccentric forces produced by active muscle contraction. The expression of these proteins after application of passive tension stimuli to muscle remains unknown. This study investigated the expression of laminin and dystrophin in the soleus muscle of rats immobilized with the right ankle in plantar flexion for 10 days and subsequent remobilization, either by isolated free movement in a cage or associated with passive stretching for up to 10 days. The intensity of the macrophage response was also evaluated. One hundred and twenty-eight female Wistar rats were divided into 8 groups: free for 10 days; immobilized for 10 days; immobilized/free for 1, 3, or 10 days; or immobilized/stretched/free for 1, 3, or 10 days. After the experimental procedures, muscle tissue was processed for immunofluorescence (dystrophin/laminin/CD68) and Western blot analysis (dystrophin/laminin). Immobilization increased the expression of dystrophin and laminin but did not alter the number of macrophages in the muscle. In the stretched muscle groups, there was an increase in dystrophin and the number of macrophages after 3 days compared with the other groups; dystrophin showed a discontinuous labeling pattern, and laminin was found in the intracellular space. The amount of laminin was increased in the muscles treated by immobilization followed by free movement for 10 days. In the initial stages of postimmobilization (1 and 3 days), an exacerbated macrophage response and an increase of dystrophin suggested that the therapeutic stretching technique induced additional stress in the muscle fibers and costameres.
Subject(s)
Animals , Female , Dystrophin/metabolism , Immobilization/methods , Laminin/metabolism , Macrophages/metabolism , Muscle Stretching Exercises/methods , Muscle, Skeletal/physiology , Blotting, Western , Dystrophin/isolation & purification , Extracellular Matrix/metabolism , Fluorescent Antibody Technique , Intracellular Space/metabolism , Laminin/isolation & purification , Mechanotransduction, Cellular/physiology , Muscle, Skeletal/injuries , Rats, WistarABSTRACT
In order to improve carrier detection of Duchenne and Becker muscular dystrophy, denucleotide sequences repeats (CA) of introns 44, 45, 49 and 50 were used as well as two markers located at the 5' and 3' ends of the dystrophin gene. Haplotypes of the unaffected and affected persons of ten DMD/BMD Mexican families were determined. Fifty eight females were studied, 30 of whom were at-risk STR haplotypes. Furthermore, it was possible to identify a recombination event in the dystrophin gene in one family, and a gonadal mosaicism was found in another family