Vera V. Ivanova

Oxidative stress, metabolic disturbances, and sex hormone imbalances resulting from preterm birth are risk factors for impaired spermatogenesis. The aim of the study was to investigate the structure of the testes of preterm, adult rats. Material and methods . The experiment involved full-term ( n  = 5) and preterm ( n  = 5) male Wistar rats at 6 months of postnatal development. Full-term rats were obtained through natural birth; their intrauterine development lasted 22 days. Preterm rats were obtained as a result of mifepristone induction of preterm labor; the duration of their intrauterine development period was 21 days. The structure of rat testes was examined by histological (hematoxylin and eosin staining) and immunohistochemical (detection of activated caspase 3) methods. Results . The testes of preterm and full-term 6-month-old rats have common features, however, in the first a decrease in the diameter of the convoluted seminiferous tubules, an increase in the number of convoluted seminiferous tubules with desquamated spermatogenic cells, as well as an increase in the number of caspase 3-positive interstitial endocrine cells were found compared with similar parameters in full-term rats. The spermatogenesis index, the number of interstitial endocrinocytes and the number of caspase 3-positive spermatogenic cells in the testes of preterm and full-term rats do not differ. Conclusions . The observed structural changes of the testes of adult preterm born rats may likely limit the adaptive potential of the testes in the postnatal period of ontogenesis.

June 11, 2026, marks the anniversary of Professor Irina Vladimirovna Sukhodolo, Doctor of Medical Sciences, Professor of the Department of Morphology and General Pathology at Siberian State Medical University. After graduating the Faculty of General Medicine at Tomsk Medical Institute, Irina Vladimirovna entered fulltime postgraduate studies at the Department of Histology, Embryology, and Cytology of Tomsk Medical Institute I.V. Sukhodolo defended her Candidate of Sciences dissertation in 1978 and her Doctor of Sciences dissertation in 1990. Today, Professor I.V. Sukhodolo is a leading histologist and an expert in the morphology of the digestive and cardiovascular systems, having founded her own morphological research school. She has published more than 450 works, 10 monographs, and 15 teaching and methodological guides. I.V. Sukhodolo has trained an entire cohort of disciples who regard her as a professional role model; among them are 25 Candidates of Sciences and 6 Doctors of Sciences. I.V. Sukhodolo steadfastly champions the necessity of medical students studying cytology, histology, embryology, and human anatomy as an integrated discipline. Through her dedicated efforts, Siberian State Medical University became home to Russia's first Department of Morphology, where students now engage in two years of uninterrupted study across all major morphological disciplines. Professor I.V. Sukhodolo's outstanding professionalism and innate intelligence, coupled with her principled nature, zero tolerance for injustice, and exquisite taste, have earned her unquestioned authority among both colleagues and students.

BACKGROUND: Newborns experience activation of the hypothalamic-pituitary-testicular axis, known as minipuberty. Preterm birth in boys has been associated with an imbalance of sex hormones during the neonatal period, but whether preterm birth affects testicular development has not been adequately studied. AIM: To provide a morphological characterization of the testes of immature rats born 24 hours preterm. METHODS: The object of the study was the testes of full-term and preterm born Wistar rats on the 14th and 28th days of the postnatal period of ontogenesis, 5 rats in each group at each time point. Full-term offspring of rats (duration of intrauterine development period is 22 days) were obtained as a result of natural birth of rats. Preterm born rat offspring (duration of intrauterine development period is 21 days) were obtained as a result of induction of preterm labor in rats with mifepristone. A histological, immunohistochemical (detection of activated caspase 3) and morphometric study of the testes of full-term and preterm rats was carried out. RESULTS: The microstructure of the testes of preterm and full-term rats on the 14th and 28th days of the postnatal period of ontogenesis is similar. However, the diameter of the convoluted seminiferous tubules of pretermy born rats on the 14th day of the postnatal period of ontogenesis is lower than that of full-term rats (p=0.000), the differences are leveled out by the 28th day. In preterm born rats, the number of interstitial endocrinocytes of the testis with morphological signs of functional activity on the 28th day of the postnatal period of ontogenesis is higher than in full-term animals (p=0.000). Preterm birth leads to an increase in the number of caspase 3-positive spermatogenic cells on the 28th day (p=0.000), as well as caspase 3-positive interstitial endocrinocytes of the testis on the 14th (p=0.000) and 28th days (p=0.000) of the postnatal period of ontogenesis. CONCLUSION: Preterm birth affects the structure of the testes of immature rats. The rate of spermatogenesis in preterm animals is unchanged, but their testes exhibit a higher rate of apoptotic death of spermatogenic and steroidogenic cells than those of full-term animals.

The aim of the study was to describe the peculiarities of the ultrastructural organization of the inner sheath of the wall of the ascending part of the aorta of rats born prematurely at 24 h and to compare them with similar structures of rats born at term. Material and methods . The study was performed on male and female Wistar rats, which were divided into 2 groups: control group (premature rats, gestational age 22 days, n=32) and experimental group (rats born 24 hours prematurely, gestational age 21 days, n=22). Premature birth Wistar rats one day before the planned time of labor. Animals of control and experimental groups were bred at 1, 2, 4, 8 and 24 weeks of postnatal development by carbon dioxide asphyxia. Fragments of the wall of the ascending part of the aorta of preterm and premature animals were analyzed using a transmission electron microscope (transmission electron microscopy). Results. In prematurely born immature animals degenerative processes in the form of swelling of organelles of synthetic and energetic apparatuses are determined in endotheliocytes of the inner sheath of the aortic wall. In the later postnatal period of ontogenesis (4-8 weeks) in sexually mature prematurely born rats, Weibel-Pallade's corpuscles, absent in prematurely born rats, are detected. In the late postnatal period of ontogenesis, vacuolization of endotheliocyte cytoplasm and thickening of the subendothelial layer, in which cells with fibroblast-like morphology are detected in prematurely born rats. Thinning and ruptures of the internal elastic membrane of the wall of the ascending part of the aorta of prematurely born rats are detected from the 4th week of the experiment. Conclusion. Premature birth leads to the development of endothelial dysfunction characterized by degenerative processes of endotheliocytes, thickening of the subendothelial layer, and thinning of the internal elastic membrane.

Rationale. At the time of birth, the innervation of the rat heart is not complete: differentiation of neurons of the autonomic ganglia, growth of axons, and development of nerve fibers sheaths continue in the postnatal period of ontogenesis. Whether preterm birth affects the innervation of the heart has not been sufficiently studied. Aim: To perform immunohistochemical study of cardiac nerve fibers of preterm rats in the postnatal period of ontogenesis. Material and Methods . A morphological study of the development of intracardiac nerve fibers in the right and left ventricles, as well as the interventricular septum of the heart in full-term and 24-hour preterm Wistar rats on the 7th, 56th and 180th days of the postnatal period of ontogenesis was carried out. Immunohistochemical detection of PGP9.5 and tyrosine hydroxylase was carried out. The relative area of nerve fibers (PGP9.5-positive staining) and sympathetic postganglionic nerve fibers (tyrosine hydroxylase-positive staining) was determined dynamically, as well as the proportion of sympathetic nerve fibers from nerve fibers total number in the wall of the right and left ventricles, as well as the interventricular septum of the heart of full-term and 24-hour preterm rats. Results. It has been shown that on the 7th day of the postnatal period of ontogenesis in the right, left ventricle and interventricular septum of the heart in 24-hour preterm rats, the relative area of nerve fibers is reduced, compared with that in full-term animals, the differences are leveled out by the 56th day. The relative area of sympathetic postganglionic nerve fibers in the interventricular septum of 24-hour preterm rats on the 7th day of the postnatal period of ontogenesis remains lower, on the 56th day – is higher than in fullterm animals. The relative area of sympathetic postganglionic nerve fibers in the right ventricle of the heart of 24-hour preterm rats throughout the experiment remains lower, while in the left ventricle – does not differ from the parameters of full-term animals. Conclusion. There were revealed structural features of the development of intracardiac nerve fibers of the right and left ventricles of the heart, as well as the interventricular septum in 24-hour preterm rats in the postnatal period of ontogenesis, which may be the cause of a violation of the autonomic regulation of the heart.

According to the classical classification, the large arteries located close to the heart are considered elastic, whereas the arteries surrounding and residing within the organs are categorized as muscular. The analysis of longitudinal arterial sections demonstrates a gradual transition from elastic to muscular vessels as the distance from the heart increases. Nonetheless, the available evidence regarding the locations at which structural changes in the human arterial media occur is limited and, in some cases, contradictory. Additionally, the morphological criteria for identifying and classifying hybrid arteries have not yet been established. This review summarizes current morphological findings on the structural changes in the human arterial media throughout the systemic and pulmonary circulation. Keywords: arteries, tunica media, histology, elastin, smooth muscle cells

Методами поляризационной микроскопии и трансмиссионной электронной микроскопии исследован сократительный аппарат кардиомиоцитов левого желудочка сердца преждевременно рождённых (на 1 сут раньше срока) 180-дневных крыс. В кардиомиоцитах преждевременно рождённых крыс миофибриллы неоднородны по толщине: наряду с истончёнными и дискомплексированными участками миофибрилл определяются утолщённые миофибриллы. Лизис миофибрилл преимущественно мелкоочаговый, реже — диффузный. Наблюдаются кардиомиоциты с субсегментарными контрактурами. В кардиомиоцитах преждевременно рождённых крыс выявляются митохондрии с признаками деструкции, в расширенных межмиофибриллярных пространствах — многочисленные мелкие митохондрии, не формирующие межмитохондриальных контактов. Повреждение митохондрий приводит к структурным и функциональным нарушениям сократительного аппарата кардиомиоцитов.

An immunohistochemical study of connexin-43 (Cx43) was carried out in the myocardium of the left ventricle of 6-month-old rats born one day preterm. Using

Telocytes are specialized interstitial cells characterized by their unique structure, which features a relatively small cell body and long cytoplasmic projections, called telopodes. Formerly referred to as interstitial Cajal-like cells, telocytes are capable of forming a complex communication network between various stromal and epithelial cell types. Despite their positive staining for CD34 and vimentin antibodies, the mesenchymal origin of these cells, as well as whether telocytes should be considered distinct cell populations or just a subpopulation of other stromal cells, remains uncertain. Telocytes have been shown to perform various functions, ranging from establishing complex three-dimensional networks, serving as an important component of stem cell niches and playing a huge role in the formation of tissue barriers, to serving as one of the key regulators of cell differentiation, having immune functions, and taking part in angiogenesis and even in organ morphogenesis. The functional diversity exhibited by telocytes in different tissues makes their study more complicated, and the exact molecular mechanisms underlying their function remain inadequately understood. As a new and intriguing field of research, telocytes hold considerable promise for improving our understanding of connective tissue physiology.