The review article presents data on extracellular vesicles (EV), bilayer phospholipid membrane structures which are secreted by different cell types and contain proteins, lipids, and nucleic acids. The features of their structure, biogenesis, and mechanisms of interaction with the recipient cell are considered. The properties of extracellular vesicles of embryonic stem cells (ESCs) and their role in the regulation of developmental processes are also considered. Special attention is paid to the vesicles of induced pluripotent stem cells (iPSCs), their role in maintaining pluripotency, and the properties of the vesicles of cells obtained during the directed differentiation of iPSCs.

Paracrine functions of mesenchymal stem (stromal) cells (MSCs) rely, at least partly, on membrane-bound extracellular vesicles (EVs) with rich composition of lipids, nucleic acids and signaling proteins. Elucidation the underlying chemistry could potentially lead to MSCs-free therapy. However, the secretome of MSCs (EVs’ composition) is non-static and depends on many other factors including surrounding cells and medium. Thus, the research techniques must be able to provide not only bulk but microscopy-scale data within a reasonable time frame. Two of these label-free techniques are subject of this work toward the question of chemical composition of the EVs.

The effectiveness of two transplantation methods of human hepatocellular carcinoma cells HepG2 and allogeneic mesenchymal stromal cells of adipose tissue (AT MSCs) into mice was compared in order to select the most effective for liver damage repair. Considerable advantage of cell transplantation into the spleen compared with intraperitoneal administration was shown. It is found that, under similar conditions of transplantation, AT MSCs are detected in liver tissue in smaller quantities than human hepatocellular carcinoma cells HepG2; differences in cell localization of these types of cells in the liver are revealed. A tendency to decrease in the degree of fibrotic changes in liver tissue after transplantation of AT MSCs and to a greater extent after transplantation of AT MSCs, pretreated with interleukin-6, was traced.

We studied the effects of melatonin on differentiation potential of Ito cells during atypical regeneration of mouse liver under conditions of CCl4-induced fibrosis. The dynamics of fibrosis was traced at the histological level and the effects of melatonin on the differentiation potential of mouse Ito cells were evaluated. Melatonin alleviated fibrotic changes in the liver tissue and reduced differentiation of Ito cells into myofibroblasts under conditions of atypical regeneration of the liver in induced fibrosis. The hepatoprotective role of melatonin was shown.

In the second part of the review we tried to consider dependence of concentration of a pinealny hormone melatonin (M) in serum of human blood. It is established that one of the main functions M is synchronization of work of all bodies, regulation of seasonal and daily rhythms of their physiological activity. It is confirmed that pregnancy and child-bearing processes directly depend on a rhythm and level of secretion of a hormone M in an organism. Also the M supports appropriate proliferative level and the immune status of a fruit. At violation of a rhythm of secretion of M at the child pathologies mental (stresses, depressions), and physiological character (a preeclampsia, an eclampsia, a fetal hypoxemia, abortions) develop. Initiation of childbirth is connected with sharp falling of concentration of M. So creation of conditions for maintenance of sufficient level of M is necessary for providing the birth of healthy posterity.

This paper presents the results of a study of developmental dynamics of pathological changes in the liver tissue of different aged mice with induced fibrosis, and also shows the role of melatonin as hepatoprotector. It was demonstrated, that the toxic damage causes more severe pathological changes in the structure of liver tissue of old animals, than of younger ones. The use of melatonin demonstrates a tendency to reduce the degree of liver fibrotization in young animals with induced fibrosis.

The proliferative activity of HaCaT keratinocytes and rat mesenchymal stromal cells (MSCs) in rats subjected to femtosecond laser pulses has been studied. The growth medium were exposed to laser pulses with a wavelength of 590 nm and duration of 30 fs. Proliferative activity was assessed from the cell number 1 day after the exposure. Cell proliferation in both cell cultures was dose-dependent within the range of 6–4299 J/cm2. Increased proliferative activity was observed at the lowest doses (32–54% for HaCaT cells and 19% for MSCs). High doses did not affect the cell growth. No increase in the reactive oxygen species was registered in the culture medium using physicochemical analysis. Femtosecond laser pulses generated acoustic oscillations from 0.5 to 6.0 kHz in the culture medium. It is proposed that the increase in the cell proliferative activity may be caused by the mechanical effects of acoustic waves produced in the environment by optical breakdown in the focus of the laser radiation.

This paper presents the results of a study of developmental dynamics of pathological changes in the liver tissue of different aged mice with induced fibrosis, and also shows the role of melatonin as hepatoprotector. It was demonstrated that the toxic damage causes more severe pathological changes in the structure of liver tissue of old animals than of younger ones. The use of melatonin demonstrates a tendency to reduce the degree of liver fibrotization in young animals with induced fibrosis.

Highly specialized muscle fibers require a unique spatial organization of the mitochondrial network. Mitochondrial morphology is largely determined by the fusion and fission of these organelles. This review summarizes the current concepts of mitochondrial dynamics mechanisms and structural features of the mitochondrial network in striated muscle tissue. The role of mitochondria and their dynamics in muscle fiber physiology are also discussed.