Figure 4: IL-17A enhances bone formation by injury-associated mesenchymal cells.

(a) The effect of IL-17A on ALP activity of injury-associated mesenchymal cells in the presence or absence of BMP-2. (b) The effect of IL-17A on in vitro mineralization as analysed by Alizarin Red S staining and quantification. (c) In vitro proliferation of injury-associated mesenchymal cells quantified by BrdU incorporation assay. (d) Proliferation of the cells within the drill hole of the wild-type and Il17a^−/− mice as quantified by in vivo BrdU incorporation assay (n=3 per genotype). BrdU⁺ cells were detected by immunofluorescence and the ratio of BrdU⁺ cells was calculated. Scale bar, 50 μm. (e) The mRNA expression levels of osteoblast genes in the injury-associated mesenchymal cells. All the data of the in vitro experiments were obtained from three independent experiments with triplicate wells. Statistical analysis was carried out using Student’s t-test throughout Fig. 4. Error bars denote the mean±s.e.m. *P<0.05.