Objective:To investigate the effect and mechanism of simvastatin on fibronectin expression in the colon of rats with Crohn’s disease (CD). Methods:The CD model was established in rats by intracolonic administration of 2,4,6-trinitrobenzene sulphonic acid (TNBS). SD rats were divided into the control group,model group,model group with simvastatin (5,20 mg/kg) group. Colonic histologic and fibrotic scores were assessed after 21 days. RT-PCR was used to detect the mRNA expression of FN,FN ED-A and FN ED-B. Western blotting was used to detect the protein expression of FN and p-MYPT-1 (representing activity of Rho-kinase). Results:In comparison with the control group,the score of histology and fibrosis,and the expression of FN and p-MYPT-1 in colonic tissue were increased obviously in the model group (P < 0.01),and reduced after administration of simvastatin (P < 0.05). Conclusions:Simvastatin is effective in preventing colonic FN expression in TNBS-induced colitis,which may result from the inhibition of the activity of Rho-kinase. It is suggested that simvastatin may prevent intestinal fibrosis in CD.