The fetomaternal interface in the placenta of three species of armadillos (Eutheria,Xenarthra,Dasypodidae).

REZENDE L; BARBEITO CG; PHAVARON P; MESS A; MIGLINO MA

REPRODUCTIVE BIOLOGY AND ENDOCRINOLOGY

BIOMED CENTRAL LTD

Año: 2012 vol. 4 p. 38 - 45

1477-7827

BackgroundPlacental characters vary among Xenarthra, one of four supraordinal clades of Eutheria.Armadillos are known for villous, haemochorial placentas similar to humans. Only the ninebandedarmadillo has been well studied so far.MethodsPlacentas of three species of armadillos were investigated by means of histology,immunohistochemistry including proliferation marker, and transmission and scanningelectron microscopy.ResultsThe gross anatomy differed: Euphractus sexcinctus and Chaetophractus villosus hadextended, zonary placentas, whereas Chaetophractus vellerosus had a disk. All taxa hadcomplex villous areas within the maternal blood sinuses of the endometrium.Immunohistochemistry indicated the validity of former interpretations that the endothelium ofthe sinuses was largely intact. Tips of the villi and the columns entering the maternal tissuepossessed trophoblast cell clusters with proliferation activity. Elsewhere, the feto-maternalbarrier was syncytial haemochorial with fetal vessels near the surface.ConclusionsDifferences among armadillos occurred in regard to the extension of the placenta, whereasthe fine structure was similar. Parallels to the human suggest that armadillos are likely to beuseful animal models for human placentation.