The effect of infrared laser irradiation on the growth of human melanoma cells in culture

Low-intensity laser irradiation exerts effects on various biological objects and is currently exploited in various branches of medicine. From a practical point of view, irradiation in the near-infrared range seems most attractive since it has the highest penetration characteristics for human tissues. In the present work, we studied the effects of 835 nm infrared low-intensity laser irradiation on two melanoma cell lines, Mel IL and MeWo, in culture. The data that we obtained indicate that low-intensity infrared irradiation impacts the growth rate of Mel IL and MeWo melanoma cell lines and that the response dynamics of the two cell lines are similar, in spite of certain quantitative differences. Stimulation of cell growth occurs within a relatively narrow range of low doses (about 0.17 J/cm 2 ). With significantly higher doses, deceleration of growth occurs instead. Рге-treatment of cells with low-dose radiation, however, protects them from the negative influence of higher doses. The protective action of low doses develops gradually, within about 10–30 min, and persists for at least 3 h. Рге-irradiation of cells also widens the range of stimulatory action with low-dose radiation. A theoretical model that explains the dynamics of cellular responses to various irradiation doses has been proposed.