Nicotine reversibly blocks RANKL-induced osteoclast formation in vitro.
a Effect on nicotine on the first (M-CSF-driven) phase of osteoclastogenesis. b Effect on nicotine on the second (M-CSF and RANKL-driven) phase of osteoclastogenesis. c–g Effect of nicotine on expression of RANKL-induced genes: c TRAP; d cathepsin K; e MMP9; f NFATc1; g RANK. h Effect of nicotine on osteoclastogenesis in the presence and absence of M-CSF in the second phase. i Osteoclast formation after 7 days of treatment with 50 ng/ml RANKL and 30 ng/ml M-CSF in the presence/absence of nicotine 500 μg/ml; osteoclast formation after 12 days of treatment with 50 ng/ml RANKL and 30 ng/ml M-CSF with presence/absence of nicotine 500 μg/ml in the first 7 days of the assay. M-CSF Macrophage colony-stimulating factor, MMP9 matrix-metalloprotease 9, NFATc1 nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1, Nic nicotine, RANK receptor activator of nuclear factor kappa B, RANKL receptor activator of nuclear factor kappa B ligand, TRAP tartrate-resistant acidic phosphatase