Bioaggregate Inhibits Osteoclast Differentiation, Fusion, and Bone Resorption In Vitro

Several bioactive bioceramics with osteoconductive effects can inhibit osteoclast formation and bone resorption in vitro, but the exact underlying mechanism has not been fully elucidated. Bioaggregate (BA), a novel calcium silicate nanoparticulate bioceramic, significantly induces bone and periodontal regeneration. In this study, we aimed to explore the effect of BA extracts on osteoclastogenesis and bone resorption.

The RAW264.7 cells were treated with soluble receptor activator of nuclear factor kappa B ligand to osteoclastogenesis. BA extracts were used to investigate the effect of BA on osteoclast differentiation, fusion, and bone resorption. Furthermore, the ions in BA extracts were quantitatively analyzed. Finally, the key molecules in the receptor activator of nuclear factor kappa B ligand-RANK signaling pathway, including receptor activator of nuclear factor κB (RANK), tumor necrosis factor receptor associated factor 6 (TRAF6), nuclear factor-kappa B (NF-κB), and nuclear factor of activated T cells c1 (NFATc1), were explored.

BA suppressed osteoclastogenesis and bone resorption in vitro. BA releases Si ions and a small amount of Sr ions and provides alkalinity. Treatment with BA extracts decreased the migration ability and fusion of RAW264.7 cells. We also observed that BA causes a significantly decreased expression of RANK, TRAF6, NF-κB, and NFATc1.

Our study provides further insight into the mechanism by which calcium silicate-based bioceramics inhibit osteoclastogenesis and bone resorption and also suggests that BA is a useful material for several clinical situations because it both stimulates osteoblast differentiation and inhibits osteoclast formation.