Effects of sorafenib on fibroblast-like synoviocyte apoptosis in rats with adjuvant arthritis.

Rheumatoid arthritis (RA) is a chronic autoimmune disease that is characterized by synovial inflammation and hyperplasia resulting from an imbalance between the proliferation and apoptosis of fibroblast-like synoviocytes (FLSs). Our previous study found that sorafenib had inhibitory effects in rats with adjuvant arthritis (AA). The present study investigated the role of sorafenib in the induction of AA FLS apoptosis in vitro. FLSs obtained from AA rats were cultured in vitro and identified. Cell apoptosis was detected using terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) and annexin V-fluorescein isothiocyanate (FITC) and propidium iodide (PI) labeling methods. Real-time PCR and Western blotting assays were used to quantify the expression levels of Fas, Caspase-3, Mcl-1, NF-κB and C-jun gene products in AA FLSs. Our data revealed that sorafenib (4 μmol/L) induced apoptosis in AA FLSs, and flow cytometry analysis showed that AA FLSs treated with sorafenib (4 μmol/L) in vitro accumulated in early and late apoptosis. There were significant increases in the expression levels of Fas, Caspase-3 and Mcl-1, and significant decreases in NF-κB and C-jun expression in AA FLSs treated with sorafenib. In summary, these results demonstrate that sorafenib promotes AA FLS apoptosis, which may be related to the upregulation of Fas and Caspase-3 and downregulation of NF-κB and C-jun. All of these findings suggest that sorafenib exerts an inhibitory effect on AA rats in vivo via AA FLS apoptotic induction, which has potential therapeutic implications for RA.