c-Src is involved in thrombin-induced HO-1 expression in synovial fibroblasts. (A, B) Osteoarthritis synovial fibroblasts (OASFs) (six OA lines) were pretreated for 30 minutes with PP2 (3 μM) or transfected with c-Src mutant for 24 hours followed by stimulation with thrombin for 24 hours, and the HO-1 expression was examined with qPCR and Western blotting. (C) OASFs (five OA lines) were incubated with thrombin for indicated time intervals, and c-Src phosphorylation was examined with Western blotting. (D) Cells (six OA lines) were pretreated 30 minutes with PPACK or rottlerin, followed by stimulation with thrombin for 30 minutes, and c-Src phosphorylation was examined with Western blotting. Results are expressed as the mean ± SEM. *P < 0.05 as compared with basal level. #P < 0.05 as compared with thrombin-treated group.