Basic Research
Copyright ©The Author(s) 2005. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Oct 7, 2005; 11(37): 5787-5794
Published online Oct 7, 2005. doi: 10.3748/wjg.v11.i37.5787
Amelioration of experimental colitis by Astragalus membranaceus through anti-oxidation and inhibition of adhesion molecule synthesis
Joshua Ka-Shun Ko, Flora Ying-Lee Lam, Andrew Pok-Lap Cheung
Joshua Ka-Shun Ko, Flora Ying-Lee Lam, Andrew Pok-Lap Cheung, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, China
Author contributions: All authors contributed equally to the work.
Supported by the HKBU Faculty Research Grant FRG/02-03/II-64
Correspondence to: Dr. Joshua Ka-Shun Ko, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.
Telephone: +852-3411-2907 Fax: +852-3411-2461
Received: December 22, 2004
Revised: March 15, 2005
Accepted: March 21, 2005
Published online: October 7, 2005

AIM: To investigate the protective effects of Astragalus membranaceus (Am) against hapten-induced colitis in male Sprague-Dawley rats as well as its underlying mechanism.

METHODS: Experimental colitis was induced in rats by enema administration of 2,4-dinitrobenzene sulfonic acid (DNBS). Rats were either pretreated with Am extract (2 or 4 g/kg, p.o. once daily) starting from 10 d before DNBS enema, or received Am post-treatment (2 or 4 g/kg, p.o. twice daily) on the three consecutive days following DNBS administration. Colonic lesion area and histological damage were determined, while the activities of myeloperoxidase (MPO) and xanthine oxidase, as well as reduced glutathione (GSH) content were measured in the excised colonic tissues. Besides, protein expression of inducible nitrite oxide synthase (iNOS), intercellular adhesion molecule-1 (ICAM-1) and P-selectin was also detected by Western blot analysis.

RESULTS: Our findings had shown that both macroscopic lesion area and histological colonic damage induced by DNBS were significantly reduced by both Am pre- and post-treatments. These were accompanied by attenuation of the elevated colonic MPO activity and downregulation of the iNOS, P-selectin, and ICAM-1 protein expression. Besides, deprivation of colonic GSH level under colitis condition was also preserved.

CONCLUSION: These results demonstrate that Am possesses both preventive and therapeutic potential in experimental colitis. The anti-inflammatory actions involve anti-oxidation along with inhibition of adhesion molecule synthesis in the colonic tissues.

Keywords: IBD, Astragalus membranaceus, Reactive oxygen metabolites, Adhesion molecules