Activation of Bone Marrow Multipotent Stromal Cells by Laser and EHF Radiation and Their Combined Impacts
The aim of the investigation was to study the effect of laser and extremely high frequency (EHF) radiations on the proliferative activity of bone marrow multipotent stromal cells (MSCs) in “normal” and “suppressed” states in vitro, as well as the ability of these factors to influence the content of MSCs in the bone marrow in vivo and in vitro. Materials and Methods. Laser radiation of low and moderate intensity, acoustic pulses generated by laser radiation in biological tissue, and EHF radiation have been used for mono and combined (applied for the first time) impacts on MSCs <i>in vivo</i> and <i>in vitro</i>. Short-term fragmentary laser heating of rat shins <i>in vivo</i> has been used to stimulate the colony-forming efficiency of MSCs. Stimulation of proliferative activity and MSCs content were studied on the strains derived from human bone marrow, rabbits, guinea pigs and rats. Irradiation of MSCs strains was performed in the “normal” state, as well as in the “suppressed” strains with the decreased proliferative activity induced by the reduction of fetal serum concentration in the nutrient medium of the cultivated cells. Exposure doses were varied by altering the power and time of irradiation. Results. A twofold increase of colony number was observed when the bone marrow was heated by a laser irradiation, and a marked stimulation of colony-forming efficiency exceeding the reference values by 85% under EHF radiation of bone marrow suspension with the dose of 8 J/cm2 was also noted. The effect of physical factors greatly depends on the MSCs state: there is a significant enhancement of proliferative activity of the cells being in the “suppressed” state. Acoustic pulses of laser-induced hydrodynamics cause a statistically significant (p<0.01) increase of proliferative activity of human MSCs (by 80% relative to the control). The proliferative activity of human MSCs was not enhanced under combined impacts compared to the exposure to mono acoustic pulses of laser-induced hydrodynamics. Conclusion. The studied physical effects <i>in vivo</i> and <i>in vitro</i> increase the content of MSCs in the initial bone marrow, as well as their proliferative activity in the process of MSCs strains development in vitro. Application of these techniques in clinic will make it possible to obtain the necessary cell number at earlier passages for autologous MSCs transplantation preventing thereby chromosomal aberrations in MSCs cultures.