Browsing by Subject "Muscle regeneration"

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    Histology of skeletal muscle reconstructed by means of the implantation of autologous adipose tissue: an experimental study
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Leiva Cepas, Fernando; Jimena, Ignacio; Ruz Caracuel, Ignacio; Luque, Evelio; Villalba, Rafael; Peña Amaro, Jose
    The purpose of this study was to determine the histological characteristics of a skeletal muscle reconstructed by means of the implantation of autologous adipose tissue following an experimentally- induced volumetric muscle loss. A cylindrical piece in the belly of the rat anterior tibial muscle was removed. In the hole, inguinal subcutaneous adipose tissue of the same rat was grafted. Animals were sacrificed 7, 14, 21, 28 and 60 days posttransplantation. Histological, histochemical, immunohistochemical and morphometric techniques were used. At all times analyzed, the regenerative muscle fibers formed from the edges of the muscle tissue showed histological, histochemical and immunohistochemical differences in comparison with the control group. These differences are related to delays in the maturation process and are related to problems in reinnervation and disorientation of muscle fibers. The stains for MyoD and desmin showed that some myoblasts and myotubes seem to derive from the transplanted adipose tissue. After 60 days, the transplant area was 20% occupied by fibrosis and by 80% skeletal muscle. However, the neo-muscle was chaotically organized showing muscle fiber disorientation and centronucleated fibers with irregular shape and size. Our results support the hypothesis that, at least from a morphological point of view, autologous adipose tissue transplantation favors reconstruction following a volumetric loss of skeletal muscle by combining the inherent regenerative response of the organ itself and the myogenic differentiation of the stem cells present in the adipose tissue. However, in our study, the formed neo- muscle exhibited histological differences in comparison with the normal skeletal muscle
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    Skeletal muscle regeneration and Trypanosoma cruzi-induced myositis in rats
    (Murcia : F. Hernández, 2004) Maldonado, I.R.S.C.; Ferreira, M.L.; Camargos, E.R.S.; Chiari, E.; Machado, C.R.S.
    Although Chagas’ disease is known to provoke severe acute myositis, information on muscle regeneration is missing. The current paper shows that during T. cruzi infection in rats, skeletal muscle parasitism and the consequent inflammatory process are higher in muscle with a high proportion of type-I myofibres (soleus and diaphragm). Immunohistochemistry showed an acute inflammatory process characterized by ED1+ and ED2+ macrophages, CD8+ lymphocytes, and NK cells. Parasite-nest rupture provoked segmental degeneration of myofibres followed by regeneration. These phenomena were observed at both light and transmission electron microscopy levels. Myofibre regeneration involved activation of satellite cells assessed by the expression of MyoD, a musclespecific transcription factor. Ultrastructural evidence of fusion of myoblast-like cells with the intact segment of degenerating fibres has been provided. At the chronic phase no signs of fibrosis were found, but sparse and small inflammatory foci were found. Our results argue against the relevant participation of autoimmunity phenomena in both acute and chronic phases and furnish a new view for explaining histopathological findings in human patient muscles.