The Effect of Pulsed Photobiomodulation on Proliferation and Migration of Human Mesenchymal Stem Cells in Vitro

Aim. To experimentally study the effect of light of different ranges on the proliferation and migration of mesenchymal stem cells of human MSCs and to select its optimal parameters for treatment. Materials and methods. The experiment was conducted in vitro on 260 cultures of human MSCs isolated from peripheral blood by magnetic separation. Cells were treated with pulsed LED light: 475 nm, 516 nm, 635 nm or left unstimulated. All LED devices had a peak radiation intensity of 80 mW/cm2. The average radiation intensity reached 40 mW/cm2. Irradiation was carried out at room temperature for 10 minutes at a distance of 2 cm from the cells. Cells embedded in a 2D fibrin gel matrix to study cell proliferation and a 3D fibrin gel matrix to study cell migration were studied. Hereby, cells used for 2D experiments were stimulated on day 0, while cells embedded in 3D arrays were stimulated on day 0 and then every 24 h until quantification. The effect of different wavelengths on both proliferation and cellular metabolic activity of MSCs from peripheral blood was evaluated after initial light treatment at 24 hours, 48 hours and 72 hours. Results. During the first 48 hours after stimulation, cells proliferated in all studied groups (stimulated and non-stimulated). At the same time, there were no significant differences between the groups at 24 hours and 48 hours. For 2D experiments, cells were stimulated only on day 0, whereas for 3D experiments, stimulation was performed every 24 h. Quantification of cells migrating into the surrounding fibrin gel matrix showed that red and green light stimulation significantly affected 3D migration after 4 days. Irradiation with blue light had no significant effect on migration. Conclusions. Thus, exposure of MSCs to red and green light increases cell proliferation in 2D and 3D environments, while exposure to blue light decreases their metabolic activity. In our opinion, this fact should be used to modernize laboratory equipment and improve treatment regimens for patients using MSCs. Further research on the influence of light on the differentiation of MSCs is promising.