Figure 1. IL-6 slightly induces osteoclast-like cells formation by mice BMMs only in the presence of sIL-6R.

(A) Schematic diagram of the culture system and assays used in this in vitro study. (B) BMMs were treated with various concentration of IL-6 alone or IL-6 and sIL-6R in combination in the presence of M-CSF (30 ng/ml) for 5 days. Then, cells were fixed with 4% PFA and subjected to TRAP staining. TRAP-positive multinucleated cells (more than three nuclei) were counted under a light microscope (original magnification, ×100). Red arrows indicate the induced TRAP-positive multinucleated cells.