Том 111, № 7 (2025)

The purpose of this review was to summarize modern concepts of endoneurial fibroblasts of peripheral nerves and their role in reparative nerve regeneration. Along with Schwann cells and macrophages, fibroblasts are the main functionally significant cells of the endoneurium. There is little information in the literature on the characteristics of fibroblasts and their role in the regeneration of damaged nerves. Recent data on the morphofunctional features of endoneurial fibroblasts, their origin in ontogenesis and their functions are presented in the review. The characteristics of immunohistochemical markers used for their identification are presented. The necessity of studying the interactions of fibroblasts with other nerve cells is emphasized to clarify their role in nerve regeneration after injury.

Previous studies have shown that two rat strains selected by the excitability threshold of the nervous system exhibit differences in response to prolonged emotional-pain stress at behavioral, neurobiological, and molecular-genetic levels, as well as specific changes in gut microbiota composition. This suggests a potential link between genetic factors, microbiota, and behavioral disturbances. The aim of this study is to analyze the gut microbiota and behavioral profiles of intact rats with high (HT) and low (LT) excitability thresholds to identify key differences driven by their genetic characteristics. The behavior of intact rats from two strains was analyzed in the Open Field and Elevated Plus Maze, and microbiota analysis in stool samples was conducted using 16S rRNA gene amplicon sequencing. Behavioral analysis revealed that high-excitable (LT) rats exhibited higher activity and less freezing in the Elevated Plus Maze compared to low-excitable (HT) rats. Alpha-diversity indices showed no significant differences between the strains, but beta-diversity analysis revealed significant differences in microbial profiles between HT and LT rats. LT rats had significantly higher abundances of Lactobacillus and Faecalibacterium genera, whereas HT rats showed a higher relative abundance of Romboutsia, Eubacterium, and Turicibacter genera. The integration of behavioral and microbiota data highlights a potential relationship between genetic factors, gut microbiota profiles, and the unique physiological and behavioral traits of rat strains selected based on the excitability threshold of the nervous system.

Currently, semaglutide, glucagon-like peptide-1 (GLP-1) receptor agonist, is widely used to treat type 2 diabetes mellitus (T2DM) and obesity, but its effect on the endocrine system functions disrupted in the diseases remains poorly understood. There are no data on the possible enhancement of the effect of semaglutide in the presence of intranasal administered insulin (IAI). The aim of the work was to study the effect of a four-week treatment of adult male rats with T2DM with semaglutide (50 μg/kg/day, subcutaneously) and its combination with IAI (2 IU/rat/day) on the hormonal parameters of the thyroid and gonadal systems. T2DM was induced by a high-fat diet and a low-dose streptozotocin. Along with glucose homeostasis parameters and insulin levels, the levels of thyroid hormones (fT4, tT4, fT3, and tT3), thyroid-stimulating hormone (TSH), testosterone and luteinizing hormone (LH) were assessed in the blood of animals. In rats with T2DM, semaglutide was shown to reduce body weight and fat mass, improve glucose tolerance and insulin sensitivity, and restore triiodothyronine levels and peripheral thyroid hormone conversion. Combined use with IAI enhanced the stimulating effects of semaglutide on the decreased levels of thyroid hormones in T2DM and normalized the increased level of TSH in T2DM and the sensitivity of the thyroid gland to TSH, assessed by the integral thyroid index. Both monotherapy with semaglutide and its combination with IAI partially restored testosterone levels decreased in T2DM, preventing androgen deficiency. Thus, semaglutide and its combination with IAI can be used to correct endocrine disorders in T2DM, which is important for clinical endocrinology and reproductive medicine.

Artificial selection of animals aimed at strengthening or weakening the defensive reaction to humans affects the variability of the functional state of regulatory systems, physiological functions of the body and the seasonality of biological cycles of reproduction and metabolism. The model object in the study of the influence of selection on the physiological functions of mammals is the seasonally breeding predator of the Mustelidae family, the American mink Neogale vison. In the course of many years of selection for a defensive reaction to humans, two lines of mink with pronounced aggressive and tame types of behavior, not typical for animals of industrial populations, were created over 27 generations. Studies of the biochemical picture of the blood serum of mammals to assess the state of metabolic processes in the body, under conditions of selection for behavior, have not been previously conducted. The aim of the work is to analyze the biochemical parameters of the blood serum of tame and aggressive American mink of cage breeding in the summer and autumn periods of the year. It is shown that both the season of the year and the type of animal behavior affect the biochemical parameters of the blood. Thus, the content of total protein, bilirubin, glucose and uric acid were higher, and the activity of alkaline phosphatase (ALP) was lower in the blood serum of animals in the autumn period compared to the summer, regardless of the type of behavior. In addition, aggressive animals had higher amylase activity, triglyceride levels, but lower lipase activity in the autumn compared to the summer period. In tame mink, the activity of aspartate aminotransferase (AST) and cholesterol levels were higher in the autumn period compared to the summer. Aggressive animals, compared to tame ones, were characterized by higher levels of albumin, glucose and cholesterol, as well as the activity of AST, lactate dehydrogenase (LDH), lipase in the summer and higher levels of glucose and LDH, but lower levels of urea and ALP in the fall. Thus, in the course of many years of selection of American mink for behavior, metabolic rates change while seasonal fluctuations in individual biochemical parameters of the blood are maintained, which reflects the evolutionary adaptive feature of mink to cyclic changes in environmental conditions.

The article presents the specifics of intra-, intermuscular, and cross-manifestations of impulse activity of various groups of afferents (Ia, Ib, and II) of the antagonist muscles of the bilateral lower legs when performing high-speed locomotor movements. The study involved 9 male athletes specializing in short-distance running who performed a locomotor test – pushing a passive treadmill belt for 10 seconds at the fastest possible speed. Electromyograms of the antagonist muscles lower legs (m. tibialis anterior, m. gastrocnemius med.) were recorded during running, followed by its processing in the MatLab program and calculation of the impulse activity of primary and secondary afferents using mathematical model based on the prediction of the triggering of muscle spindles. It has been established that high-speed running is a cross intramuscular EMG pattern of tension of the antagonist muscles of the bilateral lower legs with a transition to their relaxation, which depends on the phase of movement. Such muscle innervation in the individual phases of a high-speed running step was manifested by effective intermuscular coordination of the flexor and extensor in the phases of stance and swing of the right leg, pronounced reciprocal relations of homonymous antagonistic muscles of the lower leg in the phases of swing of the right and stance of the left legs. Intramuscular proprioceptive afferentation of the antagonist muscles lower legs of high-speed movement is characterized by the manifestation of strong impulse activity of afferents Ib, moderate afferents II and weak Ia afferents of flexors and extensors of the of symmetrical legs. A phase-dependent modulation of the intermuscular afferentation of the primary and secondary fibers of the flexors and extensors of the bilateral lower legs in the phases of stance and swing of a high-speed running step is shown. The cross-interactions of afferent activity of homologous muscles of the bilateral lower legs in different phases of movement, characteristic of a high-speed running step, have been established. The identified features of intramuscular, intermuscular, and cross-limb afferent activity during running reflect their key role in regulating the inhibitory interneuron network of the spinal cord, which maintains targeted muscle contraction and modulates motor output parameters as a whole. The supposed reflex mechanisms of high-speed locomotor movements are discussed on the basis of well-known phenomena associated with the interaction of various afferent inputs to the spinal cord neuronal apparatus in the system of lower leg antagonist muscles.

A flow system model simulating the hemodynamic process in capillaries was created to study neutrophil migration. It was found that the general patterns of neutrophil behavior (aggregate formation, formation of neutrophil tethers and migration of neutrophils along intercellular contacts of endothelial cells) are reproduced both in the control (system without chemoattractants) and in the experiment (system with low-molecular chemoattractants of bacteria), however, in the case of S. aureus and P. mirabilis using as a chemoattractant, the number of aggregates and neutrophil tethers increases statistically significantly (p < 0.05). Aggregates correspond to the swarming phenomenon in the transendothelial migration system and help limit the zone of bacterial damage. And neutrophil tethers cause a stop in hemodynamic movement and can cause either a transition to migration or be precursors to the formation of elongated neutrophil-derived structures with high antibacterial potential. Thus, all the observed phenomena contribute to the implementation of the protective function in case of bacteremia.

Coronary heart disease (CHD) is a multifactorial pathology, the progression of which is associated with the development of chronic heart failure (CHF) after a myocardial infarction (MI). Recent studies have shown that vitamin D deficiency is an independent risk factor for coronary heart disease and the severity of its course. Due to the lack of a unified understanding of the pathogenetic role of vitamin D deficiency, it is relevant to study the relationship of vitamin D deficiency with myocardial remodeling after myocardial infarction in rats. The purpose of the study. To study echocardiographic and morphological parameters of postinfarction myocardial remodeling in rats with vitamin D deficiency. Vitamin D deficiency was modeled in male Wistar stock rats (n = 41) by feeding them for two months with Delta Feeds with zero vitamin D content, followed by IM modeling. The animals were divided into 3 groups: 1st – the comparison group, 2nd – rats that did not receive cholecalciferol after MI, 3rd – those who received cholecalciferol after MI. Echocardiography was performed on a high-resolution ultrasound machine MyLabTouchSL 3116 on the 30th and 60th days of the experiment after IM modeling. Content 25(ОН)D in blood serum D was determined in 5 individuals from each group by the enzyme immunoassay (ELISA). Histological examination determined the size of the scar and assessed the severity of myocardial remodeling. Level of 25(OH)D in rats from group 3 was higher than in animals from comparison group 1 and group 2 (59.70 (50.50–64.80) nmol/L, 9.00 (8.12–9.54) nmol/l and 8.20 (7.60–8.31) nmol/l, respectively; p = 0.04). Cholecalciferol therapy was accompanied by a decrease in heart rate in group 3 compared with this indicator in group 2 (p = 0.0004) on day 30 after MI. Compared with group 3, animals from group 2 had a higher end diastolic size (EDS) (p = 0.002), end systolic size (ESS) (p = 0.002) and lower left ventricular shortness fraction (SF) (p = 0.002) and ejection fraction (EF) (p = 0.002) on days 30 and 60 after ischemic myocardial injury. The scar area as a percentage of the LV wall area, LV wall thickness in the area of the scar and interventricular septum (IVS), hypertrophy and dilation indices, taking into account the thickness of the LV walls, were higher in group 2 than in group 3 (p < 0.05). In an experimental MI model in rats with vitamin D deficiency, those who did not receive cholecalciferol therapy after MI had a significant development of myocardial hypertrophy, decreased left ventricular function, and a larger postinfarction scar area than those who received cholecalciferol.