SOST and sclerosteosis: cultured MLO-Y4 osteocytes were exposed to different concentrations of titanium (Ti) particles, cell viability was measured using the Cell Counting Kit-8 (CCK-8) assay, apoptosis of MLO-Y4 cells was evaluated by flow cytometry, Real-time PCR quantification of mRNA expression of SOST, at the same time with Western Blot detection sclerosteosis protein expression levels.MC3T3-E1 cells culture with MLO-Y4 cells exposed to different concentrations of titanium (Ti) particles in vitro, in order to detection of osteoblast osteogenetic activity.