Figure 4

The culture supernatant from Cyr61-treated FLS promotes neutrophil migration. The FLS were treated with Cyr61 protein (5 μg/ml) for 48 hours and the culture supernatant was harvested. After that, the supernatant was pre-treated with anti-IL-8 antibody (5 μg/ml) or control IgG (5 μg/ml) for 1 hour and used for a chemotaxis assay as described in Methods. (A) Neutrophils that migrated in response to the culture supernatant from Cyr61-treated FLS were stained with crystal violet. (B) The culture supernatant from Cyr61-treated FLS promoted neutrophil migration and this chemotactic response was inhibited by anti-IL-8 antibody. The results are expressed as the chemotactic index, being the number of cells that migrated towards the sample divided by the number of cells that migrated towards the control medium. Data represent the mean ± SEM of at least three independent experiments. * P <0.05, ** P <0.01. FLS, fibroblast-like synoviocytes; SEM, standard error of the mean.