Intraperitoneal treatment with imatinib suppresses mast cell-independent MSU crystal-induced acute arthritis.

(A) Changes in ankle thickness after i.a injection of 0.5 mg MSU in mast cell-deficient KitW-sh/W-sh mice (n = 6/group) pre-treated with imatinib (100 mg/kg) or PBS twice a day starting 24 h before the injection of MSU crystals. Data are shown as means ± SEM of data pooled from the two independent experiments performed. *** = P < 0.001 vs. indicated group by repeated measures two-way ANOVA. (B) H&E-stained sections of ankle showing MSU injection sites 24 h after injection of 0.5 mg MSU crystals in KitW-sh/W-sh mice pre-treated with imatinib (100 mg/kg) or PBS. Original magnification: x20.