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Chorioallantoic placentation in Galea spixii (Rodentia, Caviomorpha, Caviidae).

Oliveira MF, Mess A, Ambrósio CE, Dantas CA, Favaron PO, Miglino MA - Reprod. Biol. Endocrinol. (2008)

Bottom Line: Placentation in Galea reveals major parallels to the guinea pig and other caviomorphs with respect to the regionalization of the placenta, the associated growing processes, as well as trophoblast invasion.A principal difference compared to the guinea pig occurred in the blood supply of the subplacenta.Characteristics of the invasion and expanding processes indicate that Galea may serve as an additional animal model that is much smaller than the guinea pig and where the subplacenta partly has access to both maternal and fetal blood systems.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Surgery, Faculty of Veterinary Medicine, University of Sao Paulo, Cidade Universitária, São Paulo, Brazil. moacir@ufersa.edu.br

ABSTRACT

Background: Placentas of guinea pig-related rodents are appropriate animal models for human placentation because of their striking similarities to those of humans. To optimize the pool of potential models in this context, it is essential to identify the occurrence of characters in close relatives.

Methods: In this study we first analyzed chorioallantoic placentation in the prea, Galea spixii, as one of the guinea pig's closest relatives. Material was collected from a breeding group at the University of Mossoró, Brazil, including 18 individuals covering an ontogenetic sequence from initial pregnancy to term. Placentas were investigated by means of histology, electron microscopy, immunohistochemistry (vimentin, alpha-smooth muscle actin, cytokeration) and proliferation activity (PCNA).

Results: Placentation in Galea is primarily characterized by an apparent regionalization into labyrinth, trophospongium and subplacenta. It also has associated growing processes with clusters of proliferating trophoblast cells at the placental margin, internally directed projections and a second centre of proliferation in the labyrinth. Finally, the subplacenta, which is temporarily supplied in parallel by the maternal and fetal blood systems, served as the center of origin for trophoblast invasion.

Conclusion: Placentation in Galea reveals major parallels to the guinea pig and other caviomorphs with respect to the regionalization of the placenta, the associated growing processes, as well as trophoblast invasion. A principal difference compared to the guinea pig occurred in the blood supply of the subplacenta. Characteristics of the invasion and expanding processes indicate that Galea may serve as an additional animal model that is much smaller than the guinea pig and where the subplacenta partly has access to both maternal and fetal blood systems.

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The fetomaternal interface inside the labyrinth. (A) Initial pregnancy, TEM. Intact endothelium (end) of a fetal capillary (fc), associated with cytotrophoblast (ct) with large intercellular spaces (arrow) and syncytial trophoblast (syt) towards the maternal blood channels (mbc). (B) Mid gestation, TEM. The interhaemal barrier is very thin. (C) Near term, TEM. Cytotrophoblast is still present in the labyrinth. Scale bars = 2 μm.
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Figure 10: The fetomaternal interface inside the labyrinth. (A) Initial pregnancy, TEM. Intact endothelium (end) of a fetal capillary (fc), associated with cytotrophoblast (ct) with large intercellular spaces (arrow) and syncytial trophoblast (syt) towards the maternal blood channels (mbc). (B) Mid gestation, TEM. The interhaemal barrier is very thin. (C) Near term, TEM. Cytotrophoblast is still present in the labyrinth. Scale bars = 2 μm.

Mentions: A labyrinth as an interface between the fetal and maternal blood systems arises as a distinct region in early pregnancy (Fig. 2C). At this stage, the endothelium of the maternal arteries has been destroyed and removed by trophoblast, as revealed by immunostaining for vimentin to identify mesenchymal cells and smooth α-actin to trace vessel walls (Fig. 9A,B). Positive records found by performing cytokeratin reveal this finding (but see methods and [7]). By contrast, fetal capillaries are enclosed by endothelium (Figs. 9B, 10A–C). The capillaries are associated with cellular trophoblast possessing large intercellular spaces and some syncytial trophoblast towards the maternal blood channels (Fig. 10A). From mid gestation on, syncytial trophoblast is more frequent and becomes dominant (Fig. 10B). The syncytiotroblast between the fetal and maternal blood system is, partly, very thin (Fig. 10B,C). However, even near term some cellular trophoblast is present (Fig. 10C).


Chorioallantoic placentation in Galea spixii (Rodentia, Caviomorpha, Caviidae).

Oliveira MF, Mess A, Ambrósio CE, Dantas CA, Favaron PO, Miglino MA - Reprod. Biol. Endocrinol. (2008)

The fetomaternal interface inside the labyrinth. (A) Initial pregnancy, TEM. Intact endothelium (end) of a fetal capillary (fc), associated with cytotrophoblast (ct) with large intercellular spaces (arrow) and syncytial trophoblast (syt) towards the maternal blood channels (mbc). (B) Mid gestation, TEM. The interhaemal barrier is very thin. (C) Near term, TEM. Cytotrophoblast is still present in the labyrinth. Scale bars = 2 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2543018&req=5

Figure 10: The fetomaternal interface inside the labyrinth. (A) Initial pregnancy, TEM. Intact endothelium (end) of a fetal capillary (fc), associated with cytotrophoblast (ct) with large intercellular spaces (arrow) and syncytial trophoblast (syt) towards the maternal blood channels (mbc). (B) Mid gestation, TEM. The interhaemal barrier is very thin. (C) Near term, TEM. Cytotrophoblast is still present in the labyrinth. Scale bars = 2 μm.
Mentions: A labyrinth as an interface between the fetal and maternal blood systems arises as a distinct region in early pregnancy (Fig. 2C). At this stage, the endothelium of the maternal arteries has been destroyed and removed by trophoblast, as revealed by immunostaining for vimentin to identify mesenchymal cells and smooth α-actin to trace vessel walls (Fig. 9A,B). Positive records found by performing cytokeratin reveal this finding (but see methods and [7]). By contrast, fetal capillaries are enclosed by endothelium (Figs. 9B, 10A–C). The capillaries are associated with cellular trophoblast possessing large intercellular spaces and some syncytial trophoblast towards the maternal blood channels (Fig. 10A). From mid gestation on, syncytial trophoblast is more frequent and becomes dominant (Fig. 10B). The syncytiotroblast between the fetal and maternal blood system is, partly, very thin (Fig. 10B,C). However, even near term some cellular trophoblast is present (Fig. 10C).

Bottom Line: Placentation in Galea reveals major parallels to the guinea pig and other caviomorphs with respect to the regionalization of the placenta, the associated growing processes, as well as trophoblast invasion.A principal difference compared to the guinea pig occurred in the blood supply of the subplacenta.Characteristics of the invasion and expanding processes indicate that Galea may serve as an additional animal model that is much smaller than the guinea pig and where the subplacenta partly has access to both maternal and fetal blood systems.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Surgery, Faculty of Veterinary Medicine, University of Sao Paulo, Cidade Universitária, São Paulo, Brazil. moacir@ufersa.edu.br

ABSTRACT

Background: Placentas of guinea pig-related rodents are appropriate animal models for human placentation because of their striking similarities to those of humans. To optimize the pool of potential models in this context, it is essential to identify the occurrence of characters in close relatives.

Methods: In this study we first analyzed chorioallantoic placentation in the prea, Galea spixii, as one of the guinea pig's closest relatives. Material was collected from a breeding group at the University of Mossoró, Brazil, including 18 individuals covering an ontogenetic sequence from initial pregnancy to term. Placentas were investigated by means of histology, electron microscopy, immunohistochemistry (vimentin, alpha-smooth muscle actin, cytokeration) and proliferation activity (PCNA).

Results: Placentation in Galea is primarily characterized by an apparent regionalization into labyrinth, trophospongium and subplacenta. It also has associated growing processes with clusters of proliferating trophoblast cells at the placental margin, internally directed projections and a second centre of proliferation in the labyrinth. Finally, the subplacenta, which is temporarily supplied in parallel by the maternal and fetal blood systems, served as the center of origin for trophoblast invasion.

Conclusion: Placentation in Galea reveals major parallels to the guinea pig and other caviomorphs with respect to the regionalization of the placenta, the associated growing processes, as well as trophoblast invasion. A principal difference compared to the guinea pig occurred in the blood supply of the subplacenta. Characteristics of the invasion and expanding processes indicate that Galea may serve as an additional animal model that is much smaller than the guinea pig and where the subplacenta partly has access to both maternal and fetal blood systems.

Show MeSH
Related in: MedlinePlus