INTRODUCTION: There is great interest in establishing resources and therapies to be used in an attempt to provide a process of muscle repair better and shorter. Two features commonly used to facilitate the healing process are the therapeutic ultrasound and laser power, however, are still scarce and sometimes contradictory scientific evidence to determine with certainty the parameters and methodology necessary to acquire these goals. OBJECTIVES: Thus, the objective of present study was to evaluate the effect of therapeutic ultrasound (US) and low level laser GaAlAs 660 nm on the proliferation of C2C12 myoblasts. MATERIALS AND METHODS: The myoblasts were cultivated in culture medium of Eagle modified by Dulbecco, containing 10% fetal bovine serum (FBS) and induced to differentiate by addition of 2% horse serum for 96h. Subsequently, cells were irradiated with US (20%, 3 MHz, and intensities of 0.2 and 0.5 W/cm² for five minutes) or with LLL (output power of 10 mW, density of 3 and 5 J/cm² for 20 seconds). The non-irradiated cells serve as controls. Three independent experiments were performed for each condition cited. Cell proliferation was evaluated after 24h and 72h using the MTT method. RESULTS: The results were statistically analyzed using analysis of variance (ANOVA/Dunnet) to verify differences between control cells (untreated) and US/LLL treated groups. The results showed no significant differences in viability and cell proliferation between LLL or US treated cells and control cells after 24h and 72h. Furthermore, it was observed no increase in the number of cells within the evaluation period after treatment, confirming the process of cell differentiation, as expected. RESULTS: In conclusion, US and the LLL, employed under the parameters described does not alter C2C12 proliferation.
Ultrasound therapy; Laser; Myoblasts; Differentiation; Proliferatio
