Objective: To investigate the influence of Chaenomeles speciosa polysaccharide (CSPS) on the histological changes and the production of inflammatory cytokines in mice with adjuvant arthritis (AA). Method: Male mice were randomly divided into normal control group

model group

CSPS high and low dose groups

positive control group (n=10 in each group). Each group was started to give medicine twice daily before model establishing for continue 3 days. After model establishing on the 8th day

medicines were given twice daily for continues 16 days. The CSPS groups were ig given the medicine 400

200 mg ·kg-1 respectively. The positive control group was ig given PAT

5.6 mg ·kg-1. The normal and model groups were ig given normal saline. AA was induced by intradermal injection of complete Freund's adjuvant (CFA) into the right hind footpad of mice. Paw swelling of AA mice was measured with volume meter. The indexes of spleen

thymus and liver were analyzed. In vitro proliferation of spleen cells was examined using MTT assay. The tumor necrosis factor-α (TNF-α)

interleukin-1β(IL-1β) and interleukin-4 (IL-4) levels production of spleen lymphocytes were measured by ELISA. Result: CSPS significantly inhibited the primary and secondary paw swelling

and decreased immune organs indexes. The spleen lymphocyte proliferation reaction of AA mice was decreased by treatment with CSPS. CSPS markedly reduced TNF-α and IL-1β levels

and increased IL-4 level in spleen lymphocyte of AA mice. Conclusion: CSPS could suppress the arthritis of AA mice. Its active mechanism may be related to inhibition of proliferation of lymphocyte and regulation for inflammatory cytokines.