HGF promoted osteoclastogenesis in vitro. Cells were cultured with RANKL alone (50 ng/mL) or M-CSF (30 ng/mL) plus RANKL (50 ng/mL) for 3d or 5d. Representative TRAP staining images of (a) RAW264.7 cells, (b) BMMs with osteoclast quantitation (n = 6). RANKL + HGF: stimulated with HGF (50 ng/mL) for 3 d; Scale bars, 100 μm. Total mRNA was respectively isolated from (c) RAW264.7 cells and (d) BMMs. SU11274: stimulated with HGF (50 ng/mL) and SU11274 (0.5 μM) for 5d (n = 3). Relative expression of nfatc1, acp5, and ctsk mRNA were tested. β-actin mRNA was detected as internal control (n = 3). Data are expressed as means ± SD; ∗p < 0.05. Experiments were repeated 3 times, and similar results were obtained.