Fig. 4.

Effect of IL-33 on osteoclast differentiation in peripheral blood (PB) and synovial fluid (SF) monocytes. a PB and b SF CD14+ monocytes were cultured with various doses of IL-33 along with 25 ng/ml M-CSF. After 21 days of culturing, TRAP-positive multinucleated cells, mature osteoclasts, were counted. Figures represent data from one of three independent experiments, and the bars represent mean ± SEM. Gene expression levels of osteoclast markers such as TRAP, NFATc1, DC-STAMP, OC-STAMP, and ATP6v0d2 were measured using real-time PCR. Data were normalized to the expression level of beta-actin and reported in relative expression units. *p < 0.05, **p < 0.01, and ***p < 0.001