Histogenetic Features of Anorectal Lining Formation in Rats During Embryogenesis
- Authors: Komarova A.S.1, Slutskaya D.R.1
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Affiliations:
- Kirov Military Medical Academy
- Issue: Vol 163, No 2 (2025)
- Pages: 115-122
- Section: Original Study Articles
- URL: https://bakhtiniada.ru/1026-3543/article/view/312121
- DOI: https://doi.org/10.17816/morph.656311
- EDN: https://elibrary.ru/ICUQNX
- ID: 312121
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Abstract
BACKGROUND: During embryonic development, the formation and differentiation of the mucosal tissues of the anal canal occur through the interaction of epithelia of different germ layer origins—ectodermal and enterodermal. The epithelial lining of the anorectal region of the rectum requires further characterization. Data on the histological structure and formation of tissue components in the anorectal canal during embryogenesis are relevant both theoretically (from an evolutionary perspective) and practically, as this region is a site of embryonic anomalies and neoplasms.
AIM: To describe the histogenetic features of anorectal lining formation in rats during embryogenesis.
METHODS: An observational, single-center, retrospective, uncontrolled study was conducted. The material consisted of the caudal portion of the anorectal canal of laboratory white rat (Rattus norvegicus) embryos at embryonic days 9, 13, 15, and 18. Morphological research methods were used. Histological analysis was performed on hematoxylin and eosin–stained sections.
RESULTS: On embryonic day 9, a cloacal membrane forms in the distal part of the embryo body. By day 13, the anorectal canal is formed and lined by cutaneous and intestinal epithelia, with a bilayered urothelium-like epithelium serving as a transitional interface. By day 15, this bilayered epithelium is replaced by clusters of rounded cells with hyperchromatic nuclei. On day 18, a clearly defined boundary is observed at the anorectal junction between the two genetically and morphologically distinct epithelia.
CONCLUSION: The findings indicate that, during embryogenesis in rats, a transient urothelium-like epithelium of the transitional zone exists between the cutaneous and intestinal segments of the anorectal canal, exhibiting distinct morphofunctional organization. In the later stages of embryogenesis, this transitional epithelium disappears, suggesting its provisional nature.
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##article.viewOnOriginalSite##About the authors
Anastasia S. Komarova
Kirov Military Medical Academy
Author for correspondence.
Email: tsirya7777777@gmail.com
ORCID iD: 0009-0004-2390-9927
SPIN-code: 6585-6771
Russian Federation, Saint Petersburg
Dina R. Slutskaya
Kirov Military Medical Academy
Email: dina_hanieva@mail.ru
ORCID iD: 0000-0003-3910-2621
SPIN-code: 2546-9393
Cand. Sci. (Biology), Associate Professor
Russian Federation, Saint PetersburgReferences
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