Effect of JSOG-6 on RANKL-induced osteoclast differentiation. (A) Cell viability was measured by the MTT method as described in the Methods. (B) Bone marrow cells (1 × 104 cells/mL) were incubated with JSOG-6 in the presence of M-CSF (30 ng/mL) and RANKL (100 ng/mL) for 5 days. Osteoclastogenesis was confirmed by TRAP staining. Data represent the mean ± S.D. (n = 3). **P < 0.01 indicates statistically significant differences from the control group. (C) The expression of TRAP was determined by Western blot analysis as described in the Methods. Data are representative of three separated experiments. β-Actin was used as an internal standard.