FIG. 5.

Osteogenic differentiation at earlier and later stage in the MSC–macrophage cocultured cells. (a) RNA expression of early osteogenic marker (Runx2 & ALP at day 7) in the MSC–macrophage at the bottom chamber were examined by quantitative PCR. The osteogenesis at a later stage (day 21) was examined by osteocalcin expression (b) and Alizarin Red staining (c). NC: no particle control; cPE: contaminated polyethylene particles. *p < 0.05; **p < 0.01; ***p < 0.005. ALP, alkaline phosphatase; Runx2, Runt-related transcription factor 2. Color images are available online.