ABSTRACT
<p><b>OBJECTIVE</b>To explore the mechanism underlying the treatment of rheumatoid arthritis by Keshiling (KSL) in the rats model of FCA-induced arthritis.</p><p><b>METHOD</b>The experimental arthritis was induced by FCA in the rats. The content of PGE2 in the inflammatory swelling toes was evaluated by ultraviolet spectrophotometric method. The ConA and LPS-induced lymphocytes proliferation and the production of interleukin-2 (IL-2) secreted by thymus were determined by MTT assay.</p><p><b>RESULT</b>Results showed that the increases of lymphocyte proliferation and IL-2 production in AIA rats could be inhibited by KSL at the concentrations of 540 and 270 mg x kg(-1) in vivo and vitro. KSL at the same doses decreased the contents of PGE2 in inflammatory swelling toes, and the decreased A values were 25.6,16.1, 10.0 (A x 10(3)), respectively. After administration of KSL in vivo at 540 and 270 mg x kg(-1) the T lymphocyte proliferation were attenuated by 32.1% and 31.0%, and the production of IL-2 was inhibited by 17.5% and 14.0% respectively. While the inhibitory rates of T lymphocyte proliferation were reduced by 39.0% and 22.1% and the production of IL-2 was diminished by 27.3% and 18.2% respectively following the administration of KSL in vitro.</p><p><b>CONCLUSION</b>KSL possesses the anti-inflammation function.</p>