Figure 4

IL-17 promotes the proliferation of synoviocytes and rescues the synoviocytes from apoptotic death induced by sodium nitroprusside (SNP) via the STAT3 pathway. (A) IL-17 protects synoviocytes from apoptotic death. RA- fibroblast-like synoviocytes (FLSs) (n = 3) were cultured with IL-17 (0, 1 and 10 ng/ml) in the presence or absence of 1 mM SNP in serum-free DMEM for 24 hours. The degree of apoptosis was assessed by flow cytometry using propidium iodide (PI) and Annexin V. Representative results are shown. (B) Phase contrast microscopy showed that treatment with IL-17 dose-dependently rescued synoviocytes from apoptotic death induced by SNP. The percentage of cell area was determined using the TOMORO analySIS TS Lite Image program (Olympus, Münster, Germany). Data are expressed as mean ± SD. *P < 0.05, **P < 0.01 compared with untreated group. (C) Apoptosis activity was assayed using a caspase 3/7 assay kit and a fluorescence luminometer. Data are expressed as mean ± SD. **P < 0.01 compared with the SNP-treated group. (D) Apoptosis activity was indicated by fluorescence using a caspase3/7 assay kit. The results of three individual experiments are shown.