Objective: To investigate the effects and potential mechanisms of icariin (ICA) on acute gouty arthritis(GA) induced by sodium urate in rats. Method: Seventy-two Sprague Dawley rats were randomly divided into normal control group

model group

ICA groups (20

40

80 mg·kg-1) and colchicine group (1.5 mg·kg-1)

6 female and 6 male rats in each group. All rats were treated with ICA or colchicine or equal volume of normal saline by intragastric administration for 7 days according to the groups. At the 5th day

the gouty arthritis model was established by injection of 3% sodium urate (100 μL) into the right ankle joint cavity of rats. The circumference of the right ankle joint and score of gait were measured during 48 h treatment after model establishment. At 48 h after GA model establishment

all rats were anesthetized

and leukocyte infiltration was observed in arthroedema and synovial tissues by hematoxylin and eosin staining; the contents of interleukin (IL)-1β

IL-6

tumor necrosis factor(TNF )-α and prostaglandin E2(PGE2 ) were determined by ELISA kit; cyclooxygenase (COX-2) protein level was measured by Western blot in joint capsule and synovial tissues. Result: In model group

the tissue around joint was swelling; gait was limping; a large number of leukocytes were infiltrating in arthroedema and synovial tissues; the contents of IL-1β

IL-6

TNF-α were significantly higher than those in normal control group (P<0.05); the PGE2 and COX-2 protein levels were also significantly increased (P<0.05). As compared with model group

all of ICA low dose

middle dose and high dose treatment significantly attenuated the joint swelling and abnormal gait

and significantly decreased leukocyte infiltration and contents of IL-1β

IL-6

TNF-α and PGE2. Conclusion: ICA can attenuate the symptoms of acute GA in rats by inhibiting the inflammatory reaction.