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©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
Astragalus polysaccharide attenuates rat experimental colitis by inducing regulatory T cells in intestinal Peyer’s patches
Hai-Mei Zhao, Yan Wang, Xiao-Ying Huang, Min-Fang Huang, Rong Xu, Hai-Yang Yue, Bu-Gao Zhou, Hong-Yan Huang, Qi-Meng Sun, Duan-Yong Liu
Hai-Mei Zhao, School of Basic Medical Sciences, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004, Jiangxi Province, China
Yan Wang, Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
Xiao-Ying Huang, Key Laboratory of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004, Jiangxi Province, China
Min-Fang Huang, Rong Xu, Hai-Yang Yue, Department of Postgraduate, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004, Jiangxi Province, China
Bu-Gao Zhou, Hong-Yan Huang, Qi-Meng Sun, Duan-Yong Liu, Science and Technology College, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004, Jiangxi Province, China
Author contributions: Zhao HM is primary author of the manuscript, and designed, performed the research; Wang Y contributed to analysis of data, as well as writing and reviewing the final manuscript; Huang XY, Huang MF, Xu R, Yue HY, Zhou BG, Huang HY and Sun QM performed the research; Liu DY was involved in project conception/design and data analysis, as well as writing and reviewing the final manuscript.
Supported by National Natural Science Foundation of China, No. 81260595 and No. 81460679; Natural Science Foundation of Jiangxi Province, No. 20122BAB215046; Chinese Scholarship Council and Jiangxi Province as visiting scholar (CSC: No. 201408360106, No. 201408360110); and the Science and Technology Project of TCM from the Department of Health of Jiangxi Province, No. 2012A017.
Institutional review board statement: All routine colonic biopsy specimens and Peyer’s patch samples from the rats were taken after ethical permission was obtained for participation in the study.
Institutional animal care and use committee statement: All procedures involving animals were reviewed and approved by the institutional Animal Care and Use Committee of Jiangxi University of Traditonal Chinese Medicine (IACUC protocol number: JZ2014-78). The experimental protocols (JZ2014-78) were approved by Biomedical Ethics Committee Experimental Animal Ethics Branch of Jiangxi University of Traditional Chinese Medicine.
Conflict-of-interest statement: All authors have declared that there is no conflict of interests.
Data sharing statement: No additional unpublished data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Dr. Duan-Yong Liu, Associate Professor, Jiangxi University of Traditional Chinese Medicine, 819 Xingwan Road, Nanchang 330004, Jiangxi Province, China. liuduanyong@163.com
Telephone: +86-791-86588407 Fax: +86-791-86588407
Received: October 22, 2015
Peer-review started: October 22, 2015
First decision: November 13, 2015
Revised: November 25, 2015
Accepted: January 17, 2016
Article in press: January 17, 2016
Published online: March 21, 2016
AIM: To explore probable mechanism underlying the therapeutic effect of Astragalus polysaccharide (APS) against experimental colitis.
METHODS: Thirty-two Sprague-Dawley rats were randomly divided into four groups. Colitis was induced with 2, 4, 6-trinitrobenzene sulfonic acid (TNBS). The rats with colitis were treated with 400 mg/kg of APS for 7 d. The therapeutic effect was evaluated by colonic weight, weight index of the colon, colonic length, and macroscopic and histological scores. The levels of regulatory T (Treg) cells in Peyer’s patches were measured by flow cytometry, and cytokines in colonic tissue homogenates were analyzed using enzyme-linked immunosorbent assay. The expression of related orphan receptor-γt (ROR-γt), IL-23 and STAT-5a was measured by Western blot.
RESULTS: After 7-d treatment with APS, the weight index of the colon, colonic weight, macroscopical and histological scores were decreased, while the colonic length was increased compared with the model group. The expression of interleukin (IL)-2, IL-6, IL-17, IL-23 and ROR-γt in the colonic tissues was down-regulated, but Treg cells in Peyer’s patches, TGF-β and STAT5a in the colonic tissues were up-regulated.
CONCLUSION: APS effectively ameliorates TNBS-induced experimental colitis in rats, probably through restoring the number of Treg cells, and inhibiting IL-17 levels in Peyer’s patches.
Core tip: Regulatory T (Treg) cells are important to maintain intact mucosal barrier, and dysfunction of Treg cells is closely associated with the development and progression of inflammatory bowel disease. Astragalus membranaceus (AM) is a Chinese herb and has been used for years to strengthen immunity and its root extract has been shown to protect rats against hapten-induced colitis. However, as a main active component of AM, it is still unknown whether Astragalus polysaccharide (APS) could protect against experimental colitis by regulating Treg cells. In our study, we found that APS effectively ameliorated 2, 4, 6-trinitrobenzene sulfonic acid-induced experimental colitis in rats, probably through restoring the number of Treg cells, and inhibiting IL-17 levels in Peyer’s patches.
