RESUMEN
Effects of phototherapy using low-level lasers depend on irradiation parameters and the type of laser used. The aim of the present study was to evaluate the effect of phototherapy on the proliferation of cultured C2C12 myoblasts under different nutritional conditions using low-level GaAlAs and InGaAlP lasers with different parameters and incubation periods. C2C12 cells cultured in regular and nutrient-deficient medium were irradiated with low-level GaAlAs (780 nm) and InGaAlP (660 nm) lasers with energy densities of 3.8, 6.3 and 10 J/cm2, and 3.8, 10 and 17.5 J/cm2, respectively. Cell proliferation was assessed 48 and 72 h after irradiation by MTT assay. There were no significant differences in cell proliferation between laser-treated myoblasts and control cultures for any of the parameters and incubation periods. Further studies are necessary to determine the correct laser parameters for optimizing the biostimulation of myoblasts.