Microanatomy of Term PlacentaInsights from Human and Wistar Rat Studies: Insights from Human and Wistar Rat Studies

Kehinde Muibat Ibiyeye; Olaleke Oluwasegun Folaranmi; Musbau Olusesan Balogun; Saheed Olalekan Rabiu; Aliyu Ibrahim  Adedo; Adeola Alabi

doi:10.4314/ajtmbr.v8i1.5

Authors

Kehinde Muibat Ibiyeye Department of Anatomy, University of Ilorin Author https://orcid.org/0000-0001-5543-0989 (unauthenticated)
Olaleke Oluwasegun Folaranmi Department of Anatomic Pathology, University of Ilorin Teaching hospital Author https://orcid.org/0000-0002-0237-8934 (unauthenticated)
Musbau Olusesan Balogun Department of Anatomic Pathology, University of Ilorin Teaching hospital Author https://orcid.org/0009-0001-5608-9740 (unauthenticated)
Saheed Olalekan Rabiu Department of Health Services, Kwara State University, Malete, Nigeria, Author https://orcid.org/0009-0006-1532-2063 (unauthenticated)
Aliyu Ibrahim Adedo Department of Medical Biochemistry, University of Ilorin Author https://orcid.org/0009-0005-4980-6165 (unauthenticated)
Adeola Alabi Department of Anatomy, University of Ilorin Author https://orcid.org/0009-0003-7774-231X (unauthenticated)

DOI:

https://doi.org/10.4314/ajtmbr.v8i1.5

Keywords:

Term placenta, microanatomy, human, Wistar rat

Abstract

Introduction: The placenta is crucial for the development and survival of the maturing foetus. Wistar rat models are widely used in biomedical research to study human biological responses. However, there is limited open-access literature on the histology of the Wistar rat placenta.

Materials and Methods: Young adult male and nulliparous female Wistar rats were obtained, acclimatized, and allowed to mate overnight. On the 20th day of gestation, the pregnant rats were euthanized, and placentas were collected and fixed in 10% neutral buffered formalin. Human placentas were sampled from patients who had normal vaginal deliveries. All samples were processed using haematoxylin-eosin, Masson trichrome, periodic acid–Schiff (PAS), and reticulin stains.

Results and Conclusion: Both human and Wistar rat placentas were haemochorial, meaning the trophoblasts in both species are in direct contact with maternal blood. Differences were observed at the foetal–maternal interface and in the presence of the yolk sac. The highly vascularized labyrinth of the rat placenta features maternal and embryonic blood spaces separated by a trilaminar trophoblast layer and embryonic endothelial cells. In contrast, human-term placental villi consist of thin-walled capillaries lined by endothelial cells surrounded by a syncytiotrophoblast layer and an inconspicuous cytotrophoblastic layer. The basal plate and chorion of the human and Wistar rat placentas have similar anatomical positions, though their morphologies differ. The distribution of PAS positivity, collagen, and reticulin fibres varies between the two species. Caution is advised when extrapolating findings from rat toxicological studies to humans.

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