TiO₂ Nanotubes Up-regulate Wnt6/?-catenin Signaling Pathway To Induce Osteogenic Differentiation Of Bone Marrow Mesenchymal Stem Cells

Background Aseptic loosening due to insufficient bone ingrowth around the prosthesis is an important reason for the failure of artificial joint replacement.The pathological change of bone infiltration around the prosthesis is that the ability of bone marrow mesenchymal stem cells(BMSCs)around the prosthesis to differentiate into osteoblasts(OB)is reduced.The classical Wnt / ?-catenin signaling pathway has been shown to play an important role in inducing osteogenesis and bone resorption.The micro-morphology of TiO2 nanotubes not only helps to improve the corrosion resistance,wear resistance and mechanical properties of prosthetic implants,but also induces osteogenic differentiation of BMSCs and promotes bone tissue formation.However,the key mechanism of TiO2 nanotube structure mediated osteogenic differentiation of BMSCs has not yet been fully elucidated.Objective Explore the role and mechanism of TiO2 nanotubes in osteogenic differentiation of BMSCsMethods The test pieces with micro-morphology of TiO2 nanotubes were constructed and BMSCs were divided into control group and TiO2 group.After exposure to 3,7,and 14 days the two groups were tested for alkaline phosphatase expression in BMSCs on the surface of the specimens using alkaline phosphatase experiments.Western Blot and reverse transcription-real-time quantitative PCR were used to further detect the relative expression of osteoblast-specific markers in BMSCs.RT-q PCR was then used to screen the expression levels of related Wnt ligands.Finally,the expression of specific markers of osteogenesis differentiation and related sites of the Wnt / ?-catenin signaling pathway was detected under the condition of specific inhibitor DKK1.Impact of differentiation.Results Compared with the control group,the expression levels of alkaline phosphatase and osteogenic differentiation-specific markers RUNX2,OPN,and OCN on the 3rd,7th,and 14 th days of the TiO2 group were significantly up-regulated and reached a peak on 14 th day.By screening six related Wnt ligands,Wnt6 expression showed a high correlation with TiO2 nanotubes.By specifically inhibiting the Wnt / ?-catenin signaling pathway,it was further verified that TiO2 nanotubes can up-regulate the expression of Wnt6 ligands,thereby activating the classical Wnt6 / ?-catenin signaling pathway to promote osteogenic differentiation of BMSCs.Conclusion The micro-morphology of TiO2 nanotubes can promote the osteogenic differentiation of BMSCs through the classic Wnt6 / ?-catenin signaling pathway in vitro and provide new insights and research ideas for improving bone growth around the prosthesis.