【Objective】To investigate the effect of interleukin (IL)-22 on the apoptosis of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS). 【Methods】 Synovium tissues collected and isolated from patients who had joint replacement surgery or arthroscopy

which were cultured by tissue culture method. Bcl-2 mRNA and Bcl-XL mRNA expression in FLS (RA

Osteoarthritis

Trauma) were determined by qRT-PCR.Bcl-2 protein expression in FLS were detected by Western Blotting. RA-FLS were treated with nitric oxide (NO) donor sodium nitroprusside (SNP) in the present or absence of rhIL-22

RA-FLS apoptosis was analyzed by flow cytometry. Effects of different concentrations of rhIL-22(0

1

10

100 ng/mL) on the expression of Bcl-2 protein level in RA-FLS and OA-FLS were detected by Western Blotting. 【Results】 The Bcl-2 mRNA (P<0.05)

Bcl-XL mRNA (P<0.01) and Bcl-2 protein (P<0.01) were increased in RA-FLS compared with OA-FLS and Trauma-FLS. Flow cytometry assay showed rhIL-22 did not affect RA-FLS apoptosis compared with control group (P>0.05)

SNP induced RA-FLS apoptosis obviously (P<0.01)

rhIL-22 prevented RA-FLS apoptosis in the presence of SNP (P<0.01). rhIL-22 could up-regulate the expression of Bcl-2 in both RA-FLS and OA-FLS (P<0.05)

but RA-FLS were more sensitive to rhIL-22.【Conclusion】 IL-22 can protect RA-FLS from SNP-induced apoptosis

at least in partly by up-regulating the expression of Bcl-2.