EFFECT OF LOW-POWER RED-LIGHT LASER IRRADIATION ON THE VIABILITY OF HUMAN SKIN FIBROBLAST

Human skin fibroblast monolayers (S-126 cell line) were exposed to las er radiation (wavelength 670 nm, power density 40 mW/cm(2)). The energ y densities were 2 J/cm(2) and 12 J/cm(2), respectively, and the irrad iation was carried out at a temperature of 22 degrees C. For fibroblas t viability evaluation, the colorimetric assay (conversion of thiazoly l blue to formazan) was used. The experiments were carried out at 37 d egrees C, in the presence of 5% CO2, and at different time periods of incubation after irradiation (2, 4, 8 h and 1, 2, 3, 4, 5 days). The r esults indicated that there was a certain stimulating effect on the lo ng-term proliferation of skin fibroblasts and that the stimulation pro ceeded in two stages, the first one 2 h and the second one 3 days post irradiation.