Fig. 2.

Hydroxychloroquine (HCQ) induces the synoviocytes apoptosis through the activation of caspase-3. (a) Increase in caspase-3 activity by HCQ. The fibroblast-like synoviocytes (FLS) were treated with various concentrations of HCQ for 12 h, and then examined for the enzymatic activity of caspase-3 by the colourimetric assay. Data are the mean ± s.d. of four independent experiments, presented as fold increase relative to the optical density of untreated cells. *P < 0·05 versus untreated cells. (b) Effect of a pretreatment with a caspase-3 inhibitor, Z-DEVD-FMK on the FLS apoptosis induced by 100 µM of HCQ. Data represented the mean ± s.d. of four independent experiments. *P < 0·05 versus untreated cells. †P < 0·05 versus cells treated with HCQ 100 µM.