The effect of MAPKs and STAT3 inhibitors on S100A9-induced IL-6 and RANKL expressions in osteocytes. MLO-Y4-A2 cells were pretreated with SB203580 (p38 inhibitor, 20 μM), U0126 (ERK inhibitor, 10 μM), SP600125 (JNK inhibitor, 10 μM), or Cryptotanshinone (STAT3 inhibitor, 10 μM) for 1 hour, and treated with S100A9 (50 nM) for 24–48 hours. ((a), (c), (e), and (g)) Total RNA was isolated at 24 hours, and mRNA expressions were analyzed by qRT-PCR. ((b), (d), (f) and (h)) Supernatant and cell lysate were collected at 48 hours, and protein levels of IL-6 and RANKL were quantified by ELISA. All results of qRT-PCR were normalized by GAPDH mRNA expression levels. Data are means ± SD (n = 3). ∗∗P < 0.01 and ∗∗∗P < 0.001 show significant differences between the indicated groups.