Titre : | Implication of the satellite cell in fibrosis of dystrophic muscle (abstract : congrès international de Myologie, 2005) |
contenu dans : | |
Auteurs : | Congrès international de myologie 2005 (International Congress of Myology 2005; 9-13 mai 2005; Nantes, France) ; Alexakis C ; Partridge T ; Bou-Gharios G |
Type de document : | Article |
Année de publication : | 2005 |
Pages : | p. 78 |
Langues: | Anglais |
Mots-clés : | collagène ; colloque ; dégenérescence de la fibre musculaire ; dystrophie musculaire de Duchenne ; fibroblaste ; fibrose ; immunohistochimie ; in vivo ; inflammation ; muscle squelettique ; myoblaste ; prolifération cellulaire ; protéine de la matrice extracellulaire ; régénération musculaire ; souris |
Résumé : |
Communication n° 420. Introduction : A distinctive feature of Duchenne muscular dystrophy (DMD) is excessive deposition of dense scar tissue, which occupies the interstitual spaces left by the dying muscle fibres. Repeated cycles of muscle degeneration and regeneration induce a chronic inflammation, an extensive cell proliferation, and the biosynthesis of matrix molecules. Conventionally, this production of scar tissue has been attributed to fibroblasts proliferating in response to inflammation coupled with growth factors secretion as part of normal tissue repair. The mechanisms leading to fibrosis in skeletal muscle and the cell types involved in such a process are poorly understood. Objective : The aim of this study is to characterize the cell type(s) that overexpress matrix proteins in dystrophic muscle fibrosis. Method : Single fibres preparation was carried out on 1 and 18 month old mdx and wild-type C57Bl/10ScSn mice, followed by immunostaining of myogenic and matrix markers. Results : Satellite cell migrate out of the fibre and undergo activation in culture media. Fibres of young mdx and C57BL/10, at 72 hours, express type I collagen, the main structural component of scar tissue. However, fibres of 12-18 month mdx mice are surrounded by an envelope of cells and matrix, that is resistant to enzymatic digestion used in the isolation of single fibres and is only found beyond 22 months in C57BL/10. We have also found two distinct cell populations that migrate from old mdx fibres: a non-myogenic population that highly expresses collagen type I and a small myogenic population that no longer expresses collagen. The source of the former population remains to be elucidated. Conclusion : We hypothesise that the ability of satellite cells to express collagen could drive these local stem cells into reparative mode and excess production of matrix proteins in the early stage of dystrophy. Furthermore, ignorance of the origin of the cellular sheet that 'envelops' the old fibres |