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

Phelipe O Favaron,Lorenna C Rezende,Andrea Mess,Claudio G Barbeito,Maria A Miglino

doi:10.1186/1477-7827-10-38

Phelipe O Favaron, Lorenna C Rezende + Show 3 more

Open Access

https://doi.org/10.1186/1477-7827-10-38

Copy DOI

Abstract

BackgroundPlacental characters vary among Xenarthra, one of four supraordinal clades of Eutheria. Armadillos are known for villous, haemochorial placentas similar to humans. Only the nine-banded armadillo 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 scanning electron microscopy.ResultsThe gross anatomy differed: Euphractus sexcinctus and Chaetophractus villosus had extended, zonary placentas, whereas Chaetophractus vellerosus had a disk. All taxa had complex villous areas within the maternal blood sinuses of the endometrium. Immunohistochemistry indicated the validity of former interpretations that the endothelium of the sinuses was largely intact. Tips of the villi and the columns entering the maternal tissue possessed trophoblast cell clusters with proliferation activity. Elsewhere, the feto-maternal barrier was syncytial haemochorial with fetal vessels near the surface.ConclusionsDifferences among armadillos occurred in regard to the extension of the placenta, whereas the fine structure was similar. Parallels to the human suggest that armadillos are likely to be useful animal models for human placentation.

Highlights

Placental characters vary among Xenarthra, one of four supraordinal clades of Eutheria
The gross anatomy of the chorioallantoic placenta differed in the three armadillos: Chaetophractus villosus (Figure 1A) and Euphractus sexcinctus had extended, zonary placentas and Chaetophractus vellerosus had a disk (Figure 2A)
Indicated by the application of vimentin and cytokeratin in Chaetophractus villosus, the blood sinuses retained parts of the endothelial border (Figures 1D,E). This regions were supplied by derivatives of the spiral arteries that had been invaded by the trophoblast (Figures 1D,E,3B)

Summary

Introduction

Placental characters vary among Xenarthra, one of four supraordinal clades of Eutheria. Armadillos are known for villous, haemochorial placentas similar to humans. Attention to rather exotic species such as armadillos were drawn from the middle of 20th century on [11,12], indicating that placental characters vary within Xenarthra. Armadillos are known for haemochorial, villous placentas [11,12,13,14] similar to the human [15], Methods Term placentas of Chaetophractus villosus and Chaetophractus vellerosus were obtained from the Museum of the University of La Plata, Argentina. Samples for SEM were fixed in 2.5% glutaraldehyde, post-fixed in 2% phosphate-buffered osmium tetroxide, critical point dried and gold sputtered.

Results

Discussion

Conclusion