OPG Inhibits PMMA Induced Osteoclastogenesis and NF-kappaB Activation in Osteoclast Precursor Cells / 대한정형외과연구학회지

ABSTRACT

PURPOSE: We investigate the effect of osteoprotegerin (OPG) on activation of osteoclastogenesis and NF-kappaB activation by PMMA (Polymethyl methacrylate) particles in osteoclast precursor cells. MATERIALS AND METHODS: Osteoclast precursor cells (CSF-1 dependent) were obtained from whole bone marrow of C57BL mouse. Four experiments included 1) different dose of RANKL (Receptor Activator of NF-kappaB ligand) treatment (0, 1, 10, 40 ng/ml) 2) PMMA treatment +/- RANKL 3) PMMA treatment with different dose of RANKL 4) PMMA treatment +/- OPG. After treatments, cultured cells were stained with TRAP (Tartrate resistant alkaline phosphatase). The activity of NF-kappaB DNA nuclear translocation was detected by EMSA (electrophoretic mobility shift assay). RESULTS: The experiments with RANKL on osteoclast precursors differentiation demonstrated a dose-dependent stimulation of osteoclastogenesis (p<0.05). Control cultures without RANKL had no osteoclasts, while maintenance in 1 ng/ml of RANKL results in low level osteoclast formation. PMMA particles activated osteoclastogenesis in RANKL-primed osteoclast precursor cells. And the effect of particles on osteoclastogenesis were dependent on RANKL concentration (p<0.03). OPG treatment significantly decreased osteoclast formation and NF-kappaB DNA binding activity by PMMA particles in osteoclast precursor cells. CONCLUSION: OPG inhibits activation of osteoclast formation and NF-kappaB DNA binding activity by PMMA particles through RANK-RANKL pathway.