Interleukin-20 Acts as a Promotor of Osteoclastogenesis and Orthodontic Tooth Movement

Figure 1

IL-20 concentration differentially regulates BMM activity, and a low concentration of IL-20 can activate ERK signalling to promote cell proliferation. BMM viability was detected by CCK8 assay. IL-20 concentration differentially regulates osteoclast formation and bone resorption capacity. (a) Cell viability analysis of IL-20-treated BMMs on days 1, 3, 5, and 7. Bars represent the of six independent experiments (). (b) BMMs treated with various concentrations of IL-20 were used to investigate the protein expression levels of ERK, GRB2, and NF-κB by western blotting during early osteoclast differentiation. Bars represent the of three independent experiments (). vs. control group; ns: not significant. (c) M-CSF-induced preosteoclasts were cultured with 30 ng/mL RANKL and various concentrations of IL-20. The control group comprised M-CSF-induced preosteoclasts cultured with 30 ng/mL M-CSF, 30 ng/mL RANKL, and 0 ng/mL IL-20; TRAP-positive staining was used to examine and measure the number of TRAP-positive osteoclasts with ≥3 nuclei. (d) A bone resorption pit assay was performed to examine osteoclast function. M-CSF-induced preosteoclasts in the control group were treated as described for the TRAP staining assay; the areas of bone resorption pits were quantified. (e and f) Expression levels of osteoclast-specific proteins (TRAP, CTSK, and MMP-9) were examined using western blotting. (g and h) Expression levels of osteoclast marker genes (RANK, CTSK, TRAP, ATP60, and c-Fos) during early osteoclast differentiation after supplementation of IL-20 at 20 ng/mL or 100 ng/mL. Bars represent the of six independent experiments (). vs. control group; N.S.: not significant.

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