Fig. 1. Effects of humanin (HN) on receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation.

(A) Bone marrow-derived macrophages (BMMs) were cultured in the presence of macrophage colony-stimulating factor (M-CSF) (30 ng/ml), RANKL (50 ng/ml), and the indicated concentrations of HN for 6 days. Cells were stained for tartrate-resistant acid phosphatase (TRAP). Scale bar, 500 µm. (B) Numbers of TRAP⁺ multinucleated cells were counted (≥ 3 nuclei). BMMs were seeded into 96-well plates and incubated with various concentrations of HN. Cell viability was measured by the MTS assay. OCs, osteoclasts.^*p < 0.05 compared with control.