Particles generated from degrading magnesium implants induce bone resorption

Abstract

In the frontier of clinical translation of biodegradable magnesium (Mg), most researchers have found cavities between bone tissue and Mg-based implants. Nevertheless, the biochemical origin driving the formation of these cavities remains unknown. Here we propose that the cavities are formed as a consequence of bone resorption induced by macrophage-mediated uptake of insoluble particles produced by magnesium degradation. To verify this possibility, we collected insoluble degradation particles (DPs) of high-purity magnesium (HP–Mg) and investigated their influences on the osteoclast formation, polarization, and osteoclast bone resorption in vitro and in vivo. It was demonstrated that DPs could induce bone resorption. The DPs promoted the activation of both nuclear factor-kappa-light-chain enhancer of activated B cells (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways and upregulated the expression of osteoclast-specific genes and proteins. These results confirm that the presence of DPs could induce bone resorption both in vitro and in vivo, providing a possible mechanism for forming cavities around Mg-based implants.