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. 2016 Jun 2;173(14):2250–2262. doi: 10.1111/bph.13506

Figure 4.

Figure 4

Dexamethasone (Dex) regulates the expression of RANKL and OPG partially through activating Mig6. (a) qRT‐PCR measurement of mRNA expression of RANKL and OPG in primary chondrocytes treated with various concentrations of dexamethasone (10, 50, 250 and 1000 nM) for 48 h (Kruskal–Wallis test). (b) qRT‐PCR measurements of mRNA expression of Mig6, EGFR, EGF, TGF‐α and heparin‐binding EGF (HB‐EGF) in fetal long bone. *P < 0.05 versus control; Mann–Whitney U‐test; n = 12 per group. (c) Immunostaining of Mig6 and phosphor‐EGFR in chondrocytes: black arrow heads show positive stained chondrocytes. (d, e) Quantification of the mean optical density of Mig6‐positive stained chondrocytes (d) and phosphorylated EGFR (e). (f) Dexamethasone dose‐dependently activates mRNA expression of Mig6 in primary chondrocytes (Kruskal–Wallis test). (g) Dexamethasone suppresses the phosphorylation of EGFR in chondrocytes through activating Mig6. Rat primary epiphyseal chondrocytes were treated with 250 nM dexamethasone with or without Mig6 siRNAs for 48 h. Cell lysates were collected for Western blotting of Mig6 and phospho‐EGFR. (h) Knockdown of Mig6 by siRNA completely blocks dexamethasone‐induced mRNA expression of OPG. Primary chondrocytes were transfected with either negative control or Mig6 siRNAs followed by dexamethasone treatment; 48 h later, the mRNA level of Mig6 was measured by qRT‐PCR. *P < 0.05 versus control; Kruskal–Wallis test; n = 7 per group. Scale bar = 200 μm.