Résumé
@#Objective To investigate the effects of Astragalus polysaccarides (APS) on 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis in rats. Methods Forty male Sprague-Dawley rats were randomly divided into five groups (n = 8 ): control group, TNBS group, low-dose APS group, high-dose APS group, and prednisone group. Experimental colitis was induced in rats by enema administration of TNBS. Rats in APS and sions and histological damages were determined, and the activity of myeloperoxidase (MPO) was measured in the excised colonic tissues. Cytokine levels including interleukin (IL)-4 and IL-10 were determined by enzyme-linked immunosorbent assay. Results Both macroscopic lesions and histological colonic damages induced by TNBS were reduced by low-dose APS treatment. These were accompanied by significantly attenuated colonic MPO activity (P = 0. 03) and the increase of IL-4 and IL-10 levels. The macroscopic lesions and MPO activities of high-dose APS group were higher than TNBS group, histological damage and level of IL-4 were lower, and level of IL-10 was higher, but all without statistical significance. Levels of IL-4 and IL-10 were lower than those of TNBS group, but there was no significant difference between prednisone group and TNBS group. Levels of IL-4 and IL-10 were significantly lower in prednisone group than in control group ( P = 0. 049, P = 0. 001 ). Conclusions Different doses of APS have different effects on TNBS-induced colitis. Lower dose of APS has the therapeutic potential inexperimental colitis, while higher dose of APS may aggravate the disease.