Thermo-photobiomodulation of stem cells

Abstract

The most important task of cell transplantology is to activate the proliferative potential of mesenchymal stem cells (MSCs) before receiving bone marrow cells from a donor. This is necessary to increase a sufficient number of MSCs in early passages, when the probability of chromosomal mutations is still low. The proliferative activity of cells can be activated using photobiomodulation (PBM) by exposure to lowintensity laser radiation in the visible and near-infrared ranges. Recently, it was shown in vitro that the combination of PBM and moderate laserinduced heating can lead to a significant increase in the efficiency of MSC colony formation. The main objectives of the study are to find the optimal parameters for such a combined effect and answer the question about the possibility of a synergistic effect of thermal heating and laser radiation. MSCs isolated from rat bone marrow were used for the experiments. MSCs were exposed to short-term laser radiation of moderate power with a wavelength of 980 nm and an energy density of 68-340 J/cm2, accompanied by moderate heating of the cell suspension. Vials with grown colonies were photographed, then their number, size and number of cells in individual colonies were determined using special digital image processing methods. It was found that under optimal parameters, exposure to laser radiation of moderate power leads to an increase in the number of colonies by 4.1±0.5 times, and the total number of cells by 3.3±0.4 times compared to the control. It has been shown that this increase in cell number occurs as a result of the synergistic effect of photobiomodulation and moderate heating. Activation of colony formation after laser stimulation of MSCs occurs due to the migration of cells from the initially formed colonies with the subsequent formation of additional colonies by separated cells.