Photobiostimulation of gingival fibroblast and vascular endothelial cell proliferation
Background and Objective: Photobiomodulation is a non-invasive method for accelerated orthodontic tooth movement. LED treatment (LEDT) increases the rate of tooth movement by more than 2-fold compared to the conventional techniques. The mechanism of action at the cellular level, however, is unclear. The aim of this study was to investigate the impact of LED treatment on the proliferation of human gingival fibroblasts (HGF) and vascular endothelial cells (HUVEC) in vitro.
Materials and Methods: HGF and HUVECs were plated in 96-well plates with a concentration of 104 cells per well. The setup was designed to irradiate the cell layer directly, with a distance of 2.5 cm below the plate. The near infrared light source was with a continuous wavelength of 850nm and a power density of 60mW/cm2. Group 1 samples were irradiated every day for 1 minute while group 2 samples were irradiated for 10 minutes during 8 days of experiment. Proliferation and viability of the cells were evaluated by the MTT assay.
Results: The impact was mostly similar for both cell lines. Viable numbers of HGF cells increased for irradiated groups in 24 hours while HUVECs were not affected for the first 72 hours. There was an increase in cell proliferation in response to 1-minute irradiation and and decrease in the 10-minute irradiation group in comparison with control groups.
Conclusion: This data suggests that while a low dose exposure to LEDT stimulates the proliferation of gingival fibroblasts and endothelial cells, higher exposure inhibits their growth and the impact of LEDT is dose-dependent.