Year: 2025
Type: article
Abstract: The study of the histotopography and morphoarchitectonics of ontogenetic transformations of the lower urinary tract in humans and laboratory mice from a comparative perspective is of significant relevance for the advancement of concurrent morphological disciplines—namely, tissue engineering, molecular medicine, and reconstructive xenotransplantation. Aim of the study. To identify the principal patterns and chronological sequence of prenatal ontogenesis of the organs and structures of the lower urinary tract in humans and laboratory mice. Material and methods. The investigation was conducted using 14 series of consecutive histological sections from human embryos and prefetuses, and 15 series from laboratory mouse embryos and prefetuses. A comprehensive array of morphological research techniques was employed, including anthropometry, morphometry, light microscopy, three-dimensional computer reconstruction, and statistical analysis. The Carnegie staging system (CS) was used to synchronize and compare the periods of prenatal development in humans and laboratory mice. The research was conducted in accordance with the main provisions of the Resolution of the First National Congress on Bioethics «General Ethical Principles of Experiments ISSN 1727-4338 https://www.bsmu.edu.ua Clinical and Experimental Pathology. 2022. Vol. 21, No. 3 (81) 28 Original research on animals» (2001), ICH GCP (1996), the Council of Europe Convention on Human Rights and Biomedicine (dated 04.04.1997) and on the protection of vertebrate animals used in experiments and other scientific purposes (dated 18.03.1986), the World Medical Association's Declaration of Helsinki on Ethical Principles for Medical Research Involving Human Subjects (1964-2008), EEC Directive No. 609 (dated 24 November 1986), Order of the Ministry of Health of Ukraine No. 616 dated 3 August 2012. The work was carried out as part of the initiative research work of the Department of Histology, Cytology and Embryology of the Bukovinian State Medical University ‘Structural and functional features of tissues and organs in ontogenesis, patterns of variant, constitutional, sex-age and comparative morphology of humans’. State registration number: 0121U110121. Terms of implementation: 01.2021-12.2025. Results. In both species, hematopoietic foci were identified within the mesoderm of the allantois at Carnegie Stage 11. During stages CS12–14, the allantoic epithelium transitioned to a multilayered structure. In both human and laboratory mouse embryos, progressive atrophy of the allantois was observed up to CS23. The allantois transformed into a cellular cord, which, along with the regressed yolk sac remnant, was localized within the umbilical cord structures. In the laboratory mouse, morphometric analysis of histological specimens and 3D reconstructions of serial sections of the lower urinary tract was used to evaluate the relative thickness of the bladder wall layers. It was found that between stages CS17 and CS23, the urinary bladder of the laboratory mouse increased in size by approximately 12-fold. By stage CS23, all compartments of the murine bladder exhibited a well-developed muscular coat, characterized by unidirectional muscle fiber bundles, indicative of the initiation of distinct muscle layer formation, specifically the development of the detrusor muscle. Conclusions. 1. Comparative analysis of morphogenesis in the lower urinary tract of humans and laboratory mice using the Carnegie staging system revealed similar ontogenetic transformation stages; however, microscopic examination showed differences, notably a less differentiated detrusor muscle and a relatively accelerated formation of the definitive bladder structure in mice. 2. By stage CS23, the urinary bladder in both human and laboratory mouse embryos exhibits features characteristic of a definitive organ. 3. The differentiation of the muscular layer in the murine bladder follows a wave-like pattern, initiating at the cranial end of the bladder primordium and progressing caudally. 4. At CS17, the proportional composition of the mouse bladder wall was as follows: 55% lamina propria of the mucosa, 5% urothelium, 5% adventitial (or serosal) layer, and 35% muscular coat. By CS23, a marked increase in the relative thickness of the muscular coat was observed (up to 70%), accompanied by a decrease in the adventitial (or serosal) layer thickness.
Authors: K. Vladychenko, O. Tsyhykalo, O. Smetaniuk
Institution: Bukovinian State Medical University
Language: English
Subfield: Urology
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W4412477751