Author:
Kanashiro Claudia,Santos Tatiana C,Miglino Maria Angelica,Mess Andrea M,Carter Anthony M
Abstract
Abstract
Background
The guinea pig is an attractive model for human pregnancy and placentation, mainly because of its haemomonochorial placental type, but is rather small in size. Therefore, to better understand the impact of body mass, we studied placental development in the capybara which has a body mass around 50 kg and a gestation period of around 150 days. We paid attention to the development of the lobulated arrangement of the placenta, the growth of the labyrinth in the course of gestation, the differentiation of the subplacenta, and the pattern of invasion by extraplacental trophoblast.
Methods
Material was collected from six animals at pregnancy stages ranging from the late limb bud stage to mid gestation. Methods included latex casts, standard histology, immunohistochemistry for cytokeratin, vimentin, alpha-smooth muscle actin, and proliferating cell nuclear antigen as well as transmission electron microscopy.
Results
At the limb bud stage, the placenta was a pad of trophoblast covered by a layer of mesoderm from which fetal vessels were beginning to penetrate at folds in the surface. By 70 days, the placenta comprised areas of labyrinth (lobes) separated by interlobular areas. Placental growth resulted predominantly from proliferation of cellular trophoblast situated in nests at the fetal side of the placenta and along internally directed projections on fetal mesenchyme. Additional proliferation was demonstrated for cellular trophoblast within the labyrinth.
Already at the limb bud stage, there was a prominent subplacenta comprising cellular and syncytial trophoblast with mesenchyme and associated blood vessels. At 90 days, differentiation was complete and similar to that seen in other hystricognath rodents. Overlap of fetal vessels and maternal blood lacunae was confirmed by latex injection of the vessels. At all stages extraplacental trophoblast was associated with the maternal arterial supply and consisted of cellular trophoblast and syncytial streamers derived from the subplacenta.
Conclusion
All important characteristics of placental development and organization in the capybara resembled those found in smaller hystricognath rodents including the guinea pig. These features apparently do not dependent on body size. Clearly, placentation in hystricognaths adheres to an extraordinarily stable pattern suggesting they can be used interchangeably as models of human placenta.
Publisher
Springer Science and Business Media LLC
Subject
Developmental Biology,Endocrinology,Reproductive Medicine,Obstetrics and Gynecology
Reference52 articles.
1. Carter AM: Animal models of human placentation. Placenta. 2007, 28 (Suppl 1): S129-S132. 10.1016/j.placenta.2007.01.014.
2. Murphy WJ, Eizirik E, Johnson WE, Zhang YP, Ryder OA, O'Brien SJ: Molecular phylogenetics and the origin of placental mammals. Nature. 2001, 409: 614-618. 10.1038/35054550.
3. Murphy WJ, Eizirik E, O'Brien SJ, Madsen O, Scally M, Douady CJ, Teeling E, Ryder OA, Stanhope MJ, de Jong WW, Springer MS: Resolution of the early placental mammal radiation using Bayesian phylogenetics. Science. 2001, 294: 2348-2351. 10.1126/science.1067179.
4. Springer MS, Murphy WJ, Eizirik E, O'Brien SJ: Molecular evidence for major placental clades. The Rise of Placental Mammals: Origins and Relationships of the Major Extant Clades. Edited by: Rose KD, Archibald JD. 2005, Baltimore: Johns Hopkins University Press, 37-49.
5. Wilson DE, Reeder DM, editors: Mammal Species of the World: A Taxonomic and Geographic Reference. 2005, Baltimore: Johns Hopkins University Press
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