Estudo Macro e Microscópico da Placenta de Termo de Capivara (Hydrochaeris hydrochaeris - Carleton, M. D. 1984) / Macroscopic and microscopic study of mature capybara placenta (Hydrochaeris hydrochaeris - CARLETON, M. D. 1984)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2001

RESUMO

South and Central America are the natural habitat of the capybara, in the areas that go from Panama to Argentina, including the Andes region. These animals are herbivorous, diurnal, semi-aquatic, gregarious and docile; they live in large groups and are potentially important for the production of high quality meat, skin and oils, largely utilized in popular medicine. In spite of their economical value for the South and Central America populations, capybaras have not yet been properly studied, not even regarding their reproductive features. In this study, special attention has been given to the macroscopic and microscopic analyses of the mature placenta, an organ of fundamental importance to the fetal development and the maintenance of the gestation. Eleven mature placentas of capybara (Hydrochaeris hydrochaeris) were used. Our results show a vitelline and a chorio - allantoic placenta, coexisting until the end of the gestation, and exhibiting an irregular discoidal shape, fixed to the mesometrial region of the uterus by the stem placenta. The chorio - allantoic placenta is formed by irregular structures that characterize the placental lobes and lobules and, under electron microscopy, the materno - fetal barrier is hemomonochorial. The main cellular placental component is largely represented by the syncytiotrophoblast in the exchange areas of the labyrinth, which form the lobular region, as well as in the interlobular area. In the labyrinthic region the trophoblast is polarized and presents typical organelles of cells, which express intense protein synthesis activity and endocytosis. The general analysis of the vascular and blood components of the placenta was suggestive of a countercurrent placental circulation. Our morphological results also show that the capybara placenta has a similar structure to that found in the guinea pig by other authors.

ASSUNTO(S)

capybara hemocorial placenta hemochorial placenta microscopy microscopia capivara macroscopy macroscopia

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