EFFECTS OF PHOTOBIOMODULATION IN OSTEOCLAST FORMATION IN VITRO: A PILOT STUDY

摘要

Introduction: Near-Infrared Light Emitting Diode (NIR-LED) photobiomodulation has been found to be effectivein improving wound healing, bone regeneration, mitochondrial function, and attenuating cellular oxidative stress.Little is known regarding the use of NIR-LED and formation of osteoclasts, which break down bone. Purpose:Determine if the use of NIR-LED 670nm photobiomodulation may attenuate or amplify osteoclast differentiation inthe RAW264.7 cell line. Methods: RAW264.7 cells were cultured for 24 hours and induced to differentiate intoosteoclasts, using the cytokine, RANKL. Cultures were divided into groups according to RANKL dose (0, 2.5, 10,25, 50 ng/ml), and different energy densities (2.25, 4.5, 45 J/cm~2), treated with light either once or on fourconsecutive days using the WARP? 75 (Quantum Devices, Barneveld, WI). Osteoclast-like cells were stained forTartrate-Resistant Acid Phosphatase (TRAP). Analysis: Multinucleated, TRAP+ cells were scored as osteoclasts,counted manually by microcopy. Results were expressed as means and standard deviations and groups werecompared by one-way ANOVA with posthoc Tukey. Results: RANKL-induced osteoclast formation byRAW264.7 cells occurred as expected in all experiments. Light-treatment alone had no observable effect. Singlelight treatment at 4.5 J/cm~2 with RANKL added (10 - 50ng/ml) suggests an amplification osteoclastogenesis, asmultiple light treatments suggest attenuation of osteoclastogenesis. Conclusion: The effects of the NIR-LEDtreatment on osteoclastogenesis are RANKL dose and light intensity-specific. We conclude, as hypothesized, thatNIR-LED light-treatment may impair RANKL-induced osteoclastogenesis, particularly when using multiple lighttreatments.