Desenvolvimento do tendão elastico de aves : caracteristicas estruturais e aspectos ultra-estruturais relacionados a região elastica e a fibrocartilagem

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

Tendons are "usua11y suited for the transmission of mechanical forces from the musc1e of origin the bone of insertion. However, in many instances there are additionaI funCtiODS and properties difrering from the tendon ordinary anay, facing different biomechanical demands. The elastic tendon of the chicken wing has an elastic region that outspends to a large extent of its length and is responsible for the main mechanical properties of this tendon. However, the presence of a fibrocartiIaginous sesamoid tums this tendon in an excellent model of the lengthwise variation in tendon mórphology and, specially, with to the investigation of factors leading to the development of the elastic and fibrocartiIaginous regions. This work has as objective the characterization of the developmental steps of the elastic region and fibrocartilage, with emphasis in the participation of cell in the collagen fibrillogenesis and elastogenesis, at the structural and ultrastructural levels. These aspects are important because they could help understanding the relationships between elastin-collagen-proteoglycans in these complex systems. This work was also considered important, because the type of cell-matrix interactions observed before, are not found in the tissues like the aorta or nuchae ligament. The methodology involved light microscopy of tissue sections after different cytochemical stainings, immunocytochemistry and transmission electron microscopy applied to samples taken from embtyos and post-hatched individuals. In this work we could show that: 1) the cells of the elastic region has an active role not on1y in the synthesis of the extra cellular components but also are involved with the establishment of specific and distinct domains for the fonnation of collagen and elastic fibers, as well as are involved with the isolation and organization of the fibrillar elements in the elastic region. 2) Fibrochondrocyte-like cells are found in the fibrocartilage besides fibroblasts, either occupying different domains and apparently being involved with the synthesis of different extracellular matrix components. 3) There is a progressive accumulation of proteog1ycans in the extracellular matrix and they are initiaIly diffuse but then restricted to the fibrochondrocyte pericellular matrix. 4) Collagen fibers/bundles are progressively thicker, arranged in as basket weave-like pattem and show thin elastic fibers found at their surfaces and in the middle-substance. 5) Though these different regions seem to derive from different mechanical demands, the specific differentiation factors could not be delineated at this point

ASSUNTO(S)

tendões cartilagem frango de corte

ACESSO AO ARTIGO

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