Protection Effect of Curcumin for Macrophage-Involved Polyethylene Wear Particle-Induced Inflammatory Osteolysis by Increasing the Cholesterol Efflux.

BACKGROUND Periprosthetic osteolysis, induced by wear particles and inflammation, is a common reason for failure of primary arthroplasty. Curcumin, a nature phenol from plants, has been reported to reduce the inflammation in macrophages. This study aimed to investigate the potential effect of curcumin on macrophage involved, wear particle-induced osteolysis and its mechanism. MATERIAL AND METHODS RAW264.7 macrophages were used to test the effects of polyethylene (PE) particles and curcumin on macrophage cholesterol efflux and phenotypic changes. A mouse model of PE particle-induced calvarial osteolysis was established to test the effects of curcumin in vivo. After 14 days of treatment, the bone quality of the affected areas was analyzed by micro-computed tomography (micro-CT) and histology, and the bone surrounding soft tissues were analyzed at the cellular and molecular levels. RESULTS We found that PE particles can stimulate osteoclastogenesis and produce an M1-like phenotype in macrophages in vitro. Curcumin enhanced the cholesterol efflux in macrophages, and maintained the M0-like phenotype under the influence of PE particles in vitro. Additionally, the cholesterol transmembrane regulators ABCA1, ABCG1, and CAV1 were enhanced by curcumin in vivo. We also found enhanced bone density, reduced osteoclastogenesis, and fewer inflammatory responses in the curcumin treated groups in our mouse osteolysis model. CONCLUSIONS Our study findings indicated that curcumin can inhibit macrophage involved osteolysis and inflammation via promoting cholesterol efflux. Maintaining the cholesterol efflux might be a potential strategy to prevent periprosthetic osteolysis after total joint arthroplasty surgery.