Artículos de revistas
Development of the inverted visceral yolk sac in three species of Caviids (Rodentia, Caviomorpha, Caviidae)
Fecha
2008Registro en:
Placenta, London, v. 29, n. 8, p. 748-752, 2008
0143-4004
10.1016/j.placenta.2008.05.007
Autor
MIGLINO, Maria Angélica
FRANCIOLLI, André Luis Rezende
OLIVEIRA, Moacir Franco de
AMBRÓSIO, Carlos Eduardo
BONATELLI, Marina
MACHADO, M. R. F
MESS, Andrea
Institución
Resumen
Guinea pig related rodents possess numerous derived placental characters. We attempt to identify diversity within the visceral yolk sac and its association with the chorioallantoic placenta in three species of caviids, two of them possessing a capsule formed by the decidua that covers the chorioallantoic placenta. The results verify that in early pregnancy all three species have an inverted yolk sac placenta. In advanced pregnancy the species differ: Galea spixii, as representative without a capsule, bear a yolk sac in apposition to the chorioallantoic placenta with signs of exchange activity until term. Galea is similar to other caviomorphs in this respect. In Dasyprocta leporina and Cuniculus paca, the representatives possessing a capsule, the yolk sac endoderm lacks signs of substance exchange. Evidently, the presence of a capsule prevents such an interaction. The variations established here must be considered if animal models for human placentation are required which have restricted access to the chorioallantoic placenta from the outside