## 1 Introduction  
The creation of highly selective drugs is inevitably accompanied by concomitant side effects. The most common manifestation of such effects is the body's immune response, which includes overreaction of the immune system and individual intolerance to the drug. Therefore, much attention is currently being paid to the search for new methods of non-drug treatment of pathological processes.  
In particular, a significant number of studies are aimed at studying the effects of physical factors on the reparative and regenerative properties of biological objects.  
Physical factors primarily affect the molecular level of the organization of living organisms, which subsequently leads to changes on the cellular and tissue levels. One of the promising physical factors is low-temperature plasma (LTP). LTP is a stream of partially ionized gas with a temperature close to the ambient value [1; 2]. The biological effect of LTP is based on the synergy of strong electric fields and electromagnetic radiation [1; 2]. In this case, the effects of these factors lead to the generation of reactive oxygen species (hydroxyl radical, superoxide anion radical, hydrogen peroxide and ozone) and reactive nitrogen species (nitrogen oxide radicals, nitrate and nitrite anions, peroxynitrite and nitric, nitrous and peroxynitrous acids) [3; 4], directly affecting the properties of the tissues and cells of living organisms.  
Currently, LTP is used in various fields, such as agriculture, the food industry, bioengineering, the purification of exhaust gases, soil and wastewater [5; 6]. Plasma reactors working with targets in humid or wet environments are of great importance for biotechnology and medicine. LTP is actively used for antimicrobial and antifungal treatment [7; 8; 9; 10]. There is evidence of the use of LTP to control bleeding, which can be used for the effective healing of wounds and burns [11; 12], as well as for the tasks of regenerative medicine. LTP is used to increase the biocompatibility of materials and improve drug delivery efficiency [13; 14; 15]. It has been shown that LTP can be used in the treatment of neoplasms. In particular, in remarkable articles, the possibility of selective cytotoxic effects from low-temperature plasma in relation to different types of human cells was reported, which made it possible to select the conditions that ensured the selective death of tumor cells [16; 17; 18]. It was established that the effect of LTP on tumor cells led to inhibition of the cell cycle and the transition of these cells to different cell death variants [19]. On the other hand, depending on the conditions and time of exposure, LTP is able to stimulate the differentiation of various types of cells (e.g., preosteoblasts, fibroblasts, immune and stem cells) [20; 21; 22; 23]. Indeed, much is known about the final effects of LTP on cells and tissues. At the same time, data on the molecular mechanisms underlying them are often scarce and contradictory. However, one could assume that these effects of LTP may be associated with the ROS-induced initiation of intracellular signaling cascades involving subcellular organelles (first of all, mitochondria), which play a crucial role in cell differentiation and proliferation processes, but also, on the other hand, trigger the mechanisms of cell death [24].  
The aim of this work was to identify the effect of low-temperature plasma generated by a high-frequency glow discharge in water vapor on the viability and proliferative activity of human bone marrow stem cells (BMSC) and to estimate the role of mitochondria in the cellular response. We have shown that LTP induces a variety of effects on mammalian cells, ranging from mitochondrial degradation and apoptosis due to the overproduction of hydrogen peroxide and lipid peroxidation to increased mitochondrial biogenesis and dynamics of the organelles, reflecting the tendency for increased cell proliferation due to the ROS-induced activation of the fibroblast growth factor (FGFb).