Astragaloside IV reduces intestinal fibrosis in rats with TNBS-induced colitis

To investigate the anti-fibrotic effects of Astragaloside IV in rats with experimental colitis, and to explore the possible mechanisms, Sprague-Dawley Rats with colitis were induced by 2,4,6-trinitrobenzene sulphonic acid (TNBS). Forty-eight rats were randomly divided into normal group, TNBS model group, SB203580 group and Astragaloside IV group. 150 mg/kg TNBS dissolved in 50% ethanol were gavaged into each rat in the three groups but not the normal group. Rat in the normal group was gavaged with an equal volume of 0.9% NaCl solution. Rats in the SB203580 group were intraperitoneally injected with 10 mg/kg of SB203580 daily for 4 days. Rats in the Astragaloside IV group were gavaged with 25, 50 or 100 mg/kg of Astragaloside IV daily for 21 days. At the end of the experiment, colon tissue samples were collected, and the injury and fibrosis of the colon were detected by HE staining and Masson collagen staining, respectively. Expression of transforming growth factor (TGF)-beta 1, connective tissue growth factor (CTGF), collagen I, collagen III, fibronectin (FN) and alpha-SMA was determined by western blotting. Compared with the TNBS model group, the histological scores and fibrosis were improved significantly in the SB203580 group as well as Astragaloside IV group. Expression of TGF-beta 1, CTGF, Collagen I, Collagen III, FN and alpha-SMA in colonic tissues in the SB203580 group and Astragaloside IV group was significantly decreased compared with that in the TNBS model group. In conclusion, Astragaloside IV reduces intestinal fibrosis in rats with TNBS-induced colitis.