Evaluation of the Proliferative Effects Induced by Low-Level Laser Therapy in Bone Marrow Stem Cell Culture

OBJECTIVE: The objective of this study was to evaluate the effect of laser irradiation on dog bone marrow stem cells. BACKGROUND DATA: Low doses of low-level red laser positively affect the viability of mesenchymal stem cells, and also increase proliferation. METHODS: Low-level laser (wavelength, 660 nm; power output, 50 mW), was applied to dog bone marrow stem cell cultures (DBMSC). The energy densities delivered varied from 1 to 12J/cm(2). The effect of the laser irradiation was evaluated on cell proliferation measured with the MTT colorimetric test, cell cycle phase, and on lipidic peroxidation (free radical production). RESULTS: The results indicate that laser irradiation to DBMSC did not change the morphology of the cells, but significantly increased their viability and the number of cells at the G2/M phase with 6, 10, and 12 J/cm(2). On the other hand, malonaldehyde production was significantly enhanced with 8 J/cm(2). CONCLUSIONS: The parameters used to irradiate DBMSC increased significantly proliferation without producing high levels of reactive oxygen species (ROS).