Survival and Proliferation of Bone Marrow Derived Mesenchymal Stem Cells Under 532 nm Laser Irradiation

Study of laser irradiation effects on cell functional properties is an actual direction in development of cell therapy. However, little is known about the influence of green light on bone marrow derived mesenchymal stem cells (BM-MSCs). The aim of this work is to study the effect of 532 nm laser irradiation on the viability and proliferation of rat BM-MSCs in a wide energy density range (from 0.5 to 6300 J/cm2). The results showed that low energy densities of irradiation (0.5, 1.5, 2.5, 5, 21 J/cm
²
) do not affect the viability and proliferation of stem cells. Statistically significant increase of the viability and proliferation of BMMSCs compared to non-irradiated cells is observed only at the energy densities of 70 and 700 J/cm
²
. However no reasonable irradiation dose dependence is found in the present work. The high energy density of irradiation (above 2100 J/cm2) causes a significant decrease of the viability and proliferation of irradiated BM-MSCs. The proliferation increase observed at the irradiation energy densities of 70 J/cm2 and 700 J/cm2 is about 9 % and corresponds well to typical values reported early for other cells and laser wavelengths. But lack of the reasonable irradiation dose dependence casts doubt on the direct mechanism of the effect of green laser radiation on cells. Our results underline the importance of studying the irradiation effects in a wide range of the energy densities.