STAT1 phosphorylation of IFN-β stimulated cells. STAT1 phosphorylation levels of (a) human osteoblasts and (b) human osteoclasts stimulated with IFN-β. Bars represent mean ± sem, n = 12 osteoporosis group, n = 11 non-osteoporosis group. ° P <0.05, °° P <0.01, °°° P <0.001 compared to the untreated cells. OBs, Osteoblasts; OCs, Osteoclasts.