The Effect And Mechanism Of Anthocyanin On CoCrMo Particle-induced Osteolysis In A Mouse Calvarial Model

Purpose: Peri-implant osteolysis(PIO)is one of the leading cause of failure after total joint arthroplasty,which is known to be associated with the suppression of osteogenesis and abnormal activation of osteoclastogenesis induced by wear particles.Thus restoring of bone homeostasis may serve as a promising strategy in the treatment of PIO.The aim of this study was to examine the effect of emodin,a natural compounds,on bone remodeling in titanium particle-induced osteolysis and further investigated its underlying mechanism in vivo and in vitro.Methods: RANKL-induced osteoclastogenesis model and cocultivation of Ti particles and osteoblast model were established to simulate the pathogenic process of Ti particleinduced osteolysis in vitro.Tartrate resistant acid phosphatase(TRAP)staining,Factin staining and Resorption pit formation assay were perform to assess the effect of emodin on osteoclasts formation and their resorption activity.Alkaline phosphatase(ALP)staining and alizarin red S(ARS)staining were conducted to evaluate the effect of emodin on osteogenic potential of osteoblast in the presence of Ti particles.Western blotting and fluorescent staining were also employed to check the phosphorylation status of three essential signaling pathways involved in the RANKLinduced osteoclastogenesis.For in vivo experiments,a classic murine calvarial osteolysis model was built.Micro-CT scanning and histological analysis were performed to evaluate the effect of emodin on Ti-particle-induced bone destruction and osteoclasts formation.Results:TRAP staining showed that emodin treatment dose-dependently abrogated the osteoclastogenesis induced by RANKL.The F-actin ring formation and bone resorption activity during osteoclastogenesis were also impaired after emodin addition.Furthermore,mechanistic study proposed by western blotting and immunofluorescent staining suggested that emodin markedly suppressed the activation of NF-?B signaling but not MAPK signaling or PI3 K signaling.For osteogenic assay,ALP staining and ARS staining unveiled the enhanced osteogenesis of osteoblasts in the presence of emodin after Ti particles stimulation.For in vivo study,Both Micro-CT scanning and histological analysis proved that,after emodin injections,the inflammatory response and bone destruction were markedly ameliorated.The number of osteoclasts generated was also diminished as revealed by TRAP staining.Conclusion: Our study suggested that emodin could restore the bone homeostasis disturbed in Ti-particle-induced osteolysis both in vitro and in vivo.Thus,Emodin could be potentially developed as a phamacological candidate for the treatment of wear particle-induced osteolysis and aseptic loosening.