Comparative analysis of different doses of coherent light (laser) and non-coherent light (light-emitting diode) on cellular necrosis and apoptosis: a study in vitro

Introduction Threshold doses of electromagnetic radiation can initiate necrosis and apoptosis in cells. The purpose of this study was to evaluate cellular apoptosis and necrosis immediately (t0) and 24 hours (t24) after irradiation with different doses of coherent light (laser) or non-coherent light (LED). Methods CHO-K1 lineage cells were irradiated with laser (810nm) or LED (945±20nm), with 24mW, contact area of 1cm2 and doses of 10, 20, 30, 40 and 50J/cm2 for 300, 660, 960, 1230 and 1620s, respectively, at both wavelengths. Cells were evaluated by fluorescence microscopy, differentiating viable, apoptotic and necrotic cells immediately and 24 hours after irradiation. Results The number of necrotic cells at t0 was higher in the LED 40 and 50J/cm2 groups (86±14 and 84±16% respectively, p