Disruption and repair of the intermediate filament lattice in rat skeletalmuscle after damaging lengthening exercise

In the present paper the effect of repeated lengthening exercise on the exp ression of cytoskeletal proteins was studied in rat skeletal muscle. Tibial is anterior muscles were subjected to an exercise session consisting of 240 lengthening (L) or shortening (S) contractions. Muscles were excised 4 day s post-exercise. Contralateral muscles served as controls (C). Western blot ting was done with antibodies against desmin and vimentin. In C and S immun ostaining yielded a regular cross-striated pattern, in L however, fibers ca n be detected without immunostaining. Western blots showed no major differe nces in the amount of desmin between C, S and L, although some proteolysis was present in L. Vimentin was absent in C and S, and prominently present i n L. These data indicate that remodeling of the intermediate filament latti ce after damage induced by lengthening exercise occurs in a differentiation like manner.