Fig. 4

Downregulation of MAPK1 enhances RANKL-mediated osteoclastogenesis. A qPCR results confirmed downregulation of Mapk1 in Raw264.7 cells co-transfected siRNAs. B-C Ctsk and Trap expression determined using qPCR in Raw264.7 cells co-transfected siRNAs in the absence of RANKL. D-E Trap + osteoclasts were identified (scale bar: 50 μm) and quantified in Raw264.7 cells (D) and BMMs (E) in the presence of RANKL. The results show an increase of Trap + osteoclasts in the siRNA groups. F-G Immunofluorescent staining (scale bar: 100 μm) and quantification of osteoclast markers CTSK and TRAP at 48 h post-transfection in the presence of RANKL. Arrows: multinucleated pre-osteoclasts. Data were analyzed using one-way ANOVA with multiple-comparisons test. *, P < 0.05; **, P < 0.01; ***, P < 0.001