The aim of study was to evaluate the immunophenotype of resident macrophages of the liver, Kupffer cells, in rats in the norm.Material and methods. The study included male Wistar rats’ samples (n=6) that presented fragments of the middle lobe of the liver taken under ether anesthesia. The obtained samples were fixed in liquid nitrogen, after that cryosections 5–7 μm thick were prepared. Histological slides were used to detect the expression of a number of macrophage markers with an antibody kit: CD68, CD206, CD 163, CD86. After the first antibodies, sections were stained with antibodies conjugated to FITC, cell nuclei were detected using DAPI, the obtained preparations were studied using a fluorescence microscope.Results. When analyzing the expression of CD68 in the rat liver, it was found that normally about 20% of the cells in the field of vision appeared to be CD68+ cells, which was consistent with the earlier study results of the authors. The number of CD163+ and CD206+ cells coincided with the number of CD68+ macrophages, while CD86+ macrophages were significantly less.Conclusions. Under normal conditions, the population of resident macrophages of the rat liver is represented by cells with pronounced expression of CD68, CD163 and CD206. A large number of CD163+ and CD206+ macrophages allows concluding that Kupffer cells are close to the M2 pro-regenerative phenotype. However, the detection of CD86+ resident macrophages indicates the presence of M1 macrophages, or the presence of normal macrophages with an intermediate M1 and M2 phenotype, in the rat liver. The revealed high content of macrophages expressing CD163 and CD206 in the liver evidences not only pro-regenerative properties of Kupffer cells, but also the close connection of macrophages with liver functions, since these receptors are involved in the utilization of hemoglobin and a number of hormones.

The role of the lungs and kidneys in liver regeneration after subtotal hepatectomy was studied on a rat model. It was found that production of hepatocyte growth factor (HGF) in the lungs and kidneys and expression of cytokine genes Il1b, Il6, Il10, and tnfa significantly increased. Analysis of the dynamics of lung macrophage population showed that accumulation of HGF and the increase in the expression of cytokine genes in the lungs were accompanied by simultaneous increase in the number of CD68(+) cells, which attested to the leading role of macrophages in activation of HGF synthesis in the lungs. Macrophage content in the kidneys after subtotal hepatectomy did not increase.

The purpose of the study was to compare the phagocytic activity of macrophages of monocytic origin both without activation and under the influence of factors of the M1 and M2 phenotype. Material and methods. Peripheral blood monocytes and Kupper liver cells of male Wistar rats were obtained by gradient centrifugation. The Kupffer cells and rat monocytes were transferred to RPMI growth medium. To activate in the direction of the M1-phenotype, LPS and IFN-γ were introduced into the medium. To activate the M2 phenotype, IL 4, IL10, and IL 13 were added to the medium. The obtained macrophage cultures were stained with antibodies to CD68. To study the phagocytic activity of macrophages, the cells were placed on plates for intravital microscopy and latex beads were added to the culture medium. Results. The macrophage cultures of monocytic origin and Kupffer cells expressed CD68 at a high level, the addition of activation factors did not change the expression of the marker. 1 hour after the addition of latex particles to the culture medium, unactivated monocytic macrophages statistically significantly absorbed particles more than Kupffer cells. Activation by factors of the M1 and M2 phenotype led to an increase in the phagocytic activity of both macrophages of monocytic origin and Kupffer cells. The most activating effect on phagocytic activity was provided by induction factors of the M1 phenotype. Conclusions. For macrophages of monocytic origin and Kupffer cells, a different dynamics of phagocytic activity is characteristic. Monocytic macrophages initially have a more pronounced absorption capacity, which gradually increases during the experiment. For Kupffer cells, a sharp fluctuation of phagocytic activity is characteristic: rapid growth and rapid saturation.

The purpose of the study was to compare the phagocytic activity of macrophages of monocytic origin both without activation and under the influence of factors of the M1 and M2 phenotype. Material and methods. Peripheral blood monocytes and Kupper liver cells of male Wistar rats were obtained by gradient centrifugation. The Kupffer cells and rat monocytes were transferred to RPMI growth medium. To activate in the direction of the M1-phenotype, LPS and IFN-γ were introduced into the medium. To activate the M2 phenotype, IL 4, IL10, and IL 13 were added to the medium. The obtained macrophage cultures were stained with antibodies to CD68. To study the phagocytic activity of macrophages, the cells were placed on plates for intravital microscopy and latex beads were added to the culture medium. Results. The macrophage cultures of monocytic origin and Kupffer cells expressed CD68 at a high level, the addition of activation factors did not change the expression of the marker. 1 hour after the addition of latex particles to the culture medium, unactivated monocytic macrophages statistically significantly absorbed particles more than Kupffer cells. Activation by factors of the M1 and M2 phenotype led to an increase in the phagocytic activity of both macrophages of monocytic origin and Kupffer cells. The most activating effect on phagocytic activity was provided by induction factors of the M1 phenotype. Conclusions. For macrophages of monocytic origin and Kupffer cells, a different dynamics of phagocytic activity is characteristic. Monocytic macrophages initially have a more pronounced absorption capacity, which gradually increases during the experiment. For Kupffer cells, a sharp fluctuation of phagocytic activity is characteristic: rapid growth and rapid saturation.

In the liver of rats subjected to subtotal liver resection (80% organ weight), the expression of sox9 gene and SOX9 protein content increased and cells with hepatocyte morphology expressing SOX9 appeared; the proportion of cells expressing cytokeratin-19 also increased. Based on these data, we cannot completely exclude the involvement of resident progenitor cells and hepatocyte reprogramming in liver regeneration after subtotal resection, however, the contribution of these processes seems to be insignificant. The leading mechanism of liver mass recovery after subtotal resection is proliferation of hepatocytes.

Short-term cell culturing on basement membrane matrix is a common and very convenient in vitro model of angiogenesis. We studied the possibility of interaction of multipotent stromal cells from the umbilical cord and Ea.hy926 endothelial cells on this model at the early and late periods of the experiment. Multipotent stromal cells alone and in combination with endothelial cells formed an unstable tubular network. Clusters formed after its disassembling later became the sprouting centers in co-culture of the two cell types, but not in pure culture of multipotent stromal cells. Multipotent stromal cells with CD31+ phenotype constitute the structural basis of newly formed stable 3D capillary-like network. Prolongation of the time of culturing and combination of the two in vitro models of angiogenesis (tubulogenesis and sprouting) allowed more complete assessment of the angiogenic potential of multipotent stromal cells.

The mechanisms of proangiogenic activity of multipotent stromal cells from human umbilical cord were analyzed in vitro. The absence of secreted forms of proangiogenic growth factor VEGF-A in the culture medium conditioned by umbilical cord-derived multipotent stromal cells was shown by ELISA. However, the possibility of paracrine stimulation of cell proliferation, mobility, and directed migration of endothelial EA.hy926 cells was demonstrated by using MTT test, Transwell system, and monolayer wound modeling. The capacity of multipotent stromal cells to acquire the phenotype of endothelium-like cells was analyzed using differentiation media of three types. It was found that VEGF-A is an essential but not sufficient inductor of differentiation of umbilical cord-derived multipotent stromal cells into CD31+ cells.

Intrasplenic allogeneic transplantation of multipotent stromal cells from the umbilical cord stimulates hepatocyte proliferation and promotes recovery of liver weight in rats after subtotal resection (80% organ weight). It can be hypothesized that this effect of multipotent stromal cells is due to more rapid recovery of the number of mitochondria and normalization of mitochondrial function of liver hepatocytes.

Despite numerous medical and surgical treatment strategies available, the problem of stress urinary incontinence (SUI) in women is still not completely resolved. Continuing research is underway to modify the sling operations and develop new bulk-enhancing agents, including the use of tissue engineering and cell technologies. To evaluate the safety and effectiveness of new methods at the preclinical stage, adequate and reproducible experimental models of SUI in laboratory animals should be used. This article presents analysis of all SUI models described in the scientific literature and the results of an experimental study comparing two primary ways of modeling, based on bilateral pudendal nerve damage in female rats. The experiment results showed that only bilateral electrocoagulation of proximal part of pudendal nerves by the posterior approach ensured a stable and long-term SUI symptoms in animals in the form of leak point pressure reduction in the urodynamic study and increase of the of the urethral lumen according to histomorphometric analysis. The results suggest that an adequate experimental SUI model is urethral rabdomiosphincter denervation by pudendal nerve electrocoagulation by the posterior surgical approach, when the nerve is damaged in the area of its separation from sciatic nerve. In this case stable and reproducible results are obtainable.

The proliferation and death of hemopoietic cells in the regenerating liver of 17-day outbred albino rat fetuses were studied during 2 days after resection of 20% of the organ. The mitotic index of hemopoietic cells in the resected liver increased signifi cantly 24 h after the operation in comparison with the control fetuses. No increase in the counts of apoptotic hemopoietic cells was detected in the regenerating liver. Hence, resection of 20% of the liver in rat fetuses stimulated the proliferation of hemopoietic cells and did not stimulate their apoptosis.

The contribution of hypertrophy of hepatocytes in the recovery of body mass on the model of liver regeneration in the rat fetus was studied. Significant increase in the size of hepatocytes and their nuclei in the regenerating liver of fetal rats in comparison with an intact were not detected. Thus, hypertrophy of the cells virtually played no role in the regeneration of the fetal liver, which is subject to the same rules as the normal growth of the body.