Morphology

The conceptual framework of the morphological sciences began to develop on a scientific basis in the 18th century. Histological structures were described using terms already applied in other biological fields, such as tissue, cell, fiber, sheath, plexus, node, membrane, nucleus, colloid, and others. In addition, new terms emerged through the combination of existing concepts with clarifying modifiers. At the same time, entirely new terms were introduced, such as centrosome, mitochondrion, endoplasmic reticulum, alongside numerous eponyms in histology and cytology. For many of these terms, the authorship remains unknown or is the subject of ongoing debate.

The modern conceptual framework of histology was largely formed by the mid-20th century and officially formalized in its second half. The culmination of the evolution of histological terminology was the development of the International Histological Nomenclature, later renamed the International Histological Terminology, where eponyms were virtually excluded. Based on this international terminology, several countries developed national histological terminology, which continue to be periodically reviewed and updated. Today, histology is considered one of the most systematically organized scientific and educational disciplines.

Management of chronic, non-healing wounds is one of the pressing challenges in surgery. Demonstrating the effectiveness of novel drugs and medical devices is essential for their implementation in clinical practice. For this purpose, many animal models of wound healing have been developed, including in small rodents, which, however, have a specific skin structure and soft tissue regeneration. This review presents comparative characteristics of the main experimental wound models, including chronic ones, and describes their benefits and limitations.

Experimental studies most commonly involve mice, rats, and rabbits due to their relatively low cost and ease of maintenance. The most widely used wound modeling method is the creation of an excisional skin defect (with or without modifications) on the back of rodents. This model is technically simple and allows for partial reproduction of various pathological conditions. Although none of the models fully replicates the chronic wound healing process, modeling in small rodents (mice, rats) and rabbits remains the primary approach for studying regeneration and evaluating the efficacy of therapeutic interventions. Excisional and incisional wound models on the back of rodents are popular due to their simplicity and reproducibility. However, a significant limitation of these models is rapid wound closure by contraction, which is uncharacteristic of human healing. Chronic wound models (splinting, tail wounds in mice or ear wounds in rabbits, hyperglycemia, and others) more accurately reproduce the healing process and better reflect clinical situations. The choice of a specific model depends on the study aims and the species-specific features of laboratory animals. Moreover, the short healing period in animals often limits the ability to assess treatment efficacy. Improving and standardizing existing wound models, as well as developing novel experimental approaches, remain important tasks for regenerative medicine and surgery.

BACKGROUND: Age-related remodeling of the mucociliary transport system (MCTS) of the airways plays a significant role in the pathogenesis of respiratory diseases. However, the available published data lacks studies of the structural and functional parameters of bronchial epithelial lining throughout postnatal development conducted under standardized conditions and using unified methodological approaches, which highlights the relevance of further research in this area.

AIM: The work aimed to investigate age-related patterns of postnatal morphogenesis of the bronchial mucociliary transport system in rats based on structural and functional analysis of the respiratory epithelium components.

METHODS: The work utilizes in vivo measurement of ciliary activity, light and electron microscopy, immunohistochemistry (using antibodies against the proliferation marker Ki-67), and morphometry. The research material consisted of respiratory epithelium from the main, lobar, and segmental bronchi of Wistar rats (n = 76) at ages of 1, 8, 14 days, and 1, 3, 6, 14, 20, and 26 months, 6–9 animals per time point.

RESULTS: In newborn rats, the bronchial tree is lined with a single-layer epithelium composed predominantly of undifferentiated cells (59%–62%) and a few ciliated cells (21%–26%). During the first postnatal month, MCTS elements undergo the most intensive and asynchronous differentiation: in the first two weeks, active ciliogenesis predominates, with the number of ciliated cells increasing by 2.2–2.7 times (p < 0.001); between days 14 and 30; goblet cell subpopulations are formed. Ciliary apparatus development proceeds faster in segmental bronchi, whereas glandular element formation occurs primarily in the main bronchi. Ciliary beat frequency is the highest in newborns (25.0–25.9 Hz), decreasing to 14.9–18.6 Hz by one month of age (p < 0.001), and subsequently stabilizing at 13.2–16.2 Hz. The formation of the typical structure of the respiratory epithelium is completed during puberty; starting from 3 months of age and throughout the entire reproductive period (6–14 months), its main structural and functional characteristics remain largely unchanged. In aging (20 months) and old (26 months) animals, the number of ciliated and goblet cells reaches its maximum, and ciliary apparatus activity is preserved. However, there is a decrease in proliferative cell count, an increase in hypertrophic ciliated cells, and the appearance of ultrastructural signs of epithelial cell damage.

CONCLUSION: Postnatal morphogenesis of the bronchial MCTS in rats continues throughout life, with the most pronounced histogenetic changes occurring during the first month after birth. Subsequent age-related changes in the mature epithelial structure are aimed at maintaining stable mucociliary clearance.

BACKGROUND: Prolonged exposure to constant light suppresses melatonin synthesis by the pineal gland and induces desynchronosis, increasing the risk of various pathological conditions, including liver dysfunction. Exogenous melatonin is known to exert a pronounced hepatoprotective effect; however, its role in protecting the liver against carbon tetrachloride (CCl₄)-induced toxicity remains insufficiently understood. Moreover, the impact of disrupted circadian rhythmicity under melatonin deficiency on the development of liver pathology, as well as the mechanisms of melatonin’s hepatoprotective action in toxic injury.

AIM: The work aimed to investigate the effects of dark deprivation and exogenous melatonin on the ultrastructure of mitochondria in rat hepatocytes under carbon tetrachloride-induced toxic liver injury.

METHODS: The study involved male Wistar rats (n = 200), aged 6 months, with a body weight of (350 ± 15) g. The animals were divided into five groups: group 1, control group, fixed light–dark cycle; group 2, dark deprivation; group 3, fixed light–dark cycle with intraperitoneal CCl₄ (in olive oil, 0.3 mg/kg) every 3 days; group 4, dark deprivation with CCl₄ every 3 days; group 5, dark deprivation with CCl₄ injections every 3 days, (intraperitoneally) and daily melatonin administration (Sigma-Aldrich, USA; intragastrically, 0.3 mg/kg).

The experiment lasted 3 weeks. The ultrastructure of hepatocytes was evaluated using transmission electron microscopy. The micromorphometric analysis of mitochondria included measurement of organelle area, quantification and length of cristae, and calculation of the concentration of inner mitochondrial membranes. The statistical analysis was performed using GraphPad Prism v8.41 (GraphPad Software, USA).

RESULTS: Dark deprivation caused marked structural changes in hepatocytes, including cytoplasmic swelling, nuclear deformation, ribosomal detachment from the endoplasmic reticulum, reduced mitochondrial number, shortened cristae, and decreased concentration of inner mitochondrial membranes. CCl₄ exposure resulted in more severe damage to hepatocytes, such as cytoplasmic vacuolization, mitochondrial swelling, and necrosis. Under dark deprivation, CCl₄ toxicity was exacerbated: total mitochondrial count decreased with compensatory enlargement, cristae were shortened, and the concentration of inner mitochondrial membranes declined, indicating reduced mitochondrial function. Melatonin has a protective effect, preserving nuclear morphology, reducing lipid vacuole accumulation, and normalizing micromorphometric parameters of mitochondria.

CONCLUSION: Pineal melatonin deficiency under dark deprivation aggravates CCl₄-induced hepatotoxicity due to induction of oxidative stress and mitochondrial dysfunction. Melatonin demonstrates a pronounced hepatoprotective effect by stabilizing hepatocyte ultrastructure and supporting energy metabolism. These findings support the use of melatonin in preventing liver damage under chronic intoxication and circadian rhythmicity disruption.

BACKGROUND: Over the past decade, the teaching of human anatomy in Russian medical universities has undergone significant changes due to several factors. The collapse of the Soviet system for supply of anatomical materials for educational purposes is the most important in this series. It resulted in a significant reduction in the visual clarity of teaching and has relegated practical dissection skills to the background. The second remarkable factor was the COVID-19 pandemic in 2019–2021, which disrupted traditional teaching formats and accelerated the adoption of distance learning methods. The third factor is a widespread integration of modern diagnostic imaging techniques into the curriculum, including X-ray, computed tomography, magnetic resonance imaging, multislice computed tomography, ultrasound, and positron emission tomography. The fourth trend is the implementation of advanced technologies for the preparation and preservation of anatomical specimens, such as polymer embalming, plastination, and corrosion casting. It is also important to consider the characteristics of today’s students, shaped by the specifics of their school education, the influence of the internet industry, and a generally high standard of living.

AIM: The work aimed to analyze current features in teaching human anatomy in Russian medical universities based on Russian scientific publications from 2015 to 2024.

METHODS: Information on the teaching of human anatomy in Russian medical universities from 2015 to 2024 was obtained through an analysis of available published sources indexed in the Russian Science Citation Index. A total of 438 keywords and 96 publications were analyzed.

RESULTS: A shift in focus has been observed: away from the discussion of traditional aspects such as the use of cadaveric anatomical specimens, dissection, Latin terminology, and the significance of the instructor’s personality, and toward innovative teaching methods, psychological aspects of learning, and the role and position of students in the educational process.

CONCLUSION: Based on the publication analysis, the authors propose that, alongside traditional approaches, the development of education using multimedia platforms (particularly interactive anatomy tables) as well as the expanded use of anatomical museum resources may represent a promising area of growth in the teaching of human anatomy.

The 9th All-Russian Congress of the Scientific Medical Society of Anatomists, Histologists, and Embryologists of Russia with international participation, titled Fundamental and Applied Morphology in the 21st Century, was held on May 28–30, 2025, at Orenburg State Medical University (OrSMU). The congress was dedicated to the 95th anniversary of Honored Scientist of the Russian Federation, Professor I.I. Kagan (OrSMU), and the 100th anniversary of Academician M.R. Sapin (Russian Academy of Medical Sciences and Russian Academy of Sciences), also an Honored Scientist of the Russian Federation. This major scientific event brought together over 700 in-person participants: morphologists, educators, postgraduate students, medical students, and healthcare professionals from more than 60 cities across Russia, as well as from Kyrgyzstan, Uzbekistan, Belarus, Germany, Malaysia, and other countries. For the first time, delegates from the newly integrated territories—the Luhansk and Donetsk People’s Republics—also took part. Over the three days of the congress, five public lectures were delivered, approximately 200 oral presentations were given, and more than 700 scientific abstracts were submitted for publication. In his presidential report, Academician D.B. Nikityuk (Russian Academy of Sciences), President of the Society, analyzed the current state of the organization, scientific achievements of all 64 regional branches, and addressed matters of international cooperation, publishing activity, organizational and educational development. Strategic directions and future perspectives for the Society were outlined and discussed. The congress featured three plenary and over 20 sectional sessions, addressing both scientific problems and issues of teaching morphological sciences, as well as topics in variant, age-related, constitutional, and regional morphology. Discussions also included the prospects of using artificial intelligence in anatomical research and education, and other current issues in anatomy, histology, embryology, and clinical anatomy. During the congress, the Young Scientist Oral Presentation Competition (13 presentations) and a poster session with 60 presenters were successfully held. In the final session, the governing bodies of the Society were elected, including the Executive Board and the Presidium for 2025–2030, and the congress resolution was adopted.