Won Bong Lim
Chosun University, South Korea
Title: Comparison of the Alendronate and irradiation with a light-emitting diode (LED) on murine osteoclastogenesis
Biography
Biography: Won Bong Lim
Abstract
Low-level laser therapy (LLLT)/LED therapy has been proposed as an alternative to conventional osteoporosis therapies. Our aim was to determine the effect of irradiation with a light-emitting diode on receptor activator of NF-κB ligand (RANKL)-mediated differentiation of mouse bone marrow macrophages into osteoclasts, and compare it to alendronate treatment. The surface of cells was irradiated with LED at 5 mW/cm2 for 60 minutes in a CO2 incubator. The differentiation of irradiated and untreated RANKL-stimulated bone marrow macrophages into osteoclasts was evaluated by tartrate-resistant acid phosphatase (TRAP) staining and by molecular methods. These included assessing mRNA expression of osteoclastic markers such as c-Fos, NFATc1, TRAP, OSCAR, MMP9, and cathepsin K; phosphorylation of various MAPKs, including extracellular signal-regulated kinase ERK1/2, P38, and JNK; NF-κB translocation; and resorption pit formation. Results were compared to those obtained with sodium alendronate. Production of reactive oxygen species was measured by a 2ʹ,7ʹ-dihydrodichlorofluorescein diacetate assay. LED irradiation and alendronate inhibited mRNA expression of osteoclast-related genes, such as TRAP, c-Fos, and NFATc1, and reduced the osteoclast activity of RANKL-stimulated bone marrow macrophages. LED irradiation, but not alendronate, also inhibited the production of reactive oxygen species; phosphorylation of ERK, P38, and IκB; and NF-κB translocation. These findings suggest that LED irradiation has an inhibitory effect on osteoclast formation; this effect could lead to reduced bone loss and may offer a new therapeutic tool for managing osteoporosis.