Basic Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Sep 21, 2018; 24(35): 4036-4053
Published online Sep 21, 2018. doi: 10.3748/wjg.v24.i35.4036
Daikenchuto (Da-Jian-Zhong-Tang) ameliorates intestinal fibrosis by activating myofibroblast transient receptor potential ankyrin 1 channel
Keizo Hiraishi, Lin-Hai Kurahara, Miho Sumiyoshi, Yao-Peng Hu, Kaori Koga, Miki Onitsuka, Daibo Kojima, Lixia Yue, Hidetoshi Takedatsu, Yu-Wen Jian, Ryuji Inoue
Keizo Hiraishi, Lin-Hai Kurahara, Miho Sumiyoshi, Yao-Peng Hu, Ryuji Inoue, Department of Physiology, Graduate School of Medical Sciences, Fukuoka University, Fukuoka 8140180, Japan
Kaori Koga, Miki Onitsuka, Department of Pathology, Faculty of Medicine, Fukuoka University, Fukuoka 8140180, Japan
Daibo Kojima, Department of Gastroenterological Surgery, Faculty of Medicine, Fukuoka University, Fukuoka 8140180, Japan
Lixia Yue, Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, United States
Hidetoshi Takedatsu, Department of Gastroenterology and Medicine, Faculty of Medicine, Fukuoka University, Fukuoka 8140180, Japan
Yu-Wen Jian, College of Letters and Science, University of California, Davis, CA 95616, United States
Author contributions: Kurahara LH designed the experiments and wrote the paper, Hiraishi K, Kurahara LH and Sumiyoshi M performed most of the experiments and analyzed the data; Hu YP conducted patch-clamp experiments and analyzed the obtained data; Koga K and Onitsuka M performed the pathological analysis; Yue L provided comments; Kojima D and Takedatsu H gave clinical advice, recruited study participants, and performed the biopsies and surgical resections of tissue; Jian YW created the graphical abstract; and Inoue R supervised the study and assisted in the preparation of the manuscript.
Supported by MEXT, KAKENHI, No. 15K08978, No. 22790677 and No. 25860571; a MEXT-Supported Program supporting research activities of female researchers; the Clinical Research Foundation; and the Central Research Institute of Fukuoka University, No. 151045 and No. 147104.
Institutional review board statement: The study was reviewed and approved by the Clinical Research Ethics Committee of Fukuoka University, No. 15-10-04.
Institutional animal care and use committee statement: All procedures involving animals were reviewed and approved by the Animal experiment ethics committee of Fukuoka University, No. 1709099; and the Genetic Modification Experiment Safety Commission of Fukuoka University approved experiments on genetically modified animals, No. 167.
Conflict-of-interest statement: The authors declare that they have no competing interests.
Data sharing statement: Readers can request the data of this paper by contacting us via
ARRIVE guidelines statement: The authors have read the ARRIVE guidelines, and the manuscript was prepared and revised according to the ARRIVE guidelines.
Correspondence to: Lin-Hai Kurahara, PhD, Lecturer, Department of Physiology, Fukuoka University School of Medicine, Fukuoka 8140180, Japan.
Telephone: +81-92-8011011-3236 Fax: +81-92-8656032
Received: May 16, 2018
Peer-review started: May 16, 2018
First decision: June 13, 2018
Revised: July 6, 2018
Accepted: July 22, 2018
Article in press: July 22, 2018
Published online: September 21, 2018
Research background

Daikenchuto (DKT) is a traditional oriental herbal medicine, widely used to mitigate post-operative ileus and constipation. The mechanism of its actions remains less understood, in particular regarding its molecular target(s). However, an important hint to addressing this issue has come from our previous findings that the transient receptor potential ankyrin 1 (TRPA1) is highly expressed in intestinal myofibroblasts and mediates the antifibrotic effects of steroid and pirfenidone.

Research motivation

We hypothesized that DKT may activate TRPA1 channels in myofibroblasts to directly counteract the fibrotic changes of inflamed intestines. Although DKT has been shown to be beneficial for gut motility, intestinal blood flow and gastrointestinal hormone secretion, its anti-fibrotic actions through TRPA1 channel activation will be an entirely new finding and of considerable clinical significance.

Research objectives

We aimed at investigating at both in vitro and in vivo levels whether DKT targets TRPA1 channels expressed in intestinal myofibroblasts to exert its anti-fibrotic actions. The results would not only disclose a novel molecular target of anti-fibrotic therapy for inflammatory bowel diseases such as Crohn’s disease (CD) and ulcerative colitis, but also promote our general understanding about the complex actions of herbal medicines.

Research methods

A trinitrobenzene sulfonic acid (TNBS) chronic colitis model was established in both wild-type and TRPA1 knock out mice, in which the impact of DKT administration were evaluated by pathological and biochemical analyses. An intestinal myofibroblast cell line (InMyoFibs) stimulated by transforming growth factor-β1 (TGF-β1) was used as a cellular model of intestinal fibrosis, where expression of TRPA1 and pro-fibrotic factors and related intracellular signaling (in particular TGF-β-mediated one) were examined in detail. The counteracting effects of DKT on these changes were also evaluated. Biopsy samples from non-stenotic and stenotic regions of CD patient’s intestines were subjected to histological examination and immunoblot analysis with particular respect to the altered expression pattern of TRPA1 channel and fibrotic factors. As compared with preceding works on a similar topic, the methodological approach applied to this study is more comprehensive covering a broad range of DKT’s actions that include cellular and animal models and human patients.

Research results

In TNBS chronic colitis model mice, the extents of inflammation and fibrotic changes were more prominent in TRPA1-/- knockout than in wild-type mice. One-week enema administration of DKT suppressed fibrotic lesions in wild-type mice, but not in TRPA1 knockout mice. Active ingredients of DKT, induced Ca2+ influxes in InMyoFib, which were antagonized by TRPA1 channel blocker HC-030031. DKT counteracted TGF-β1-induced expression of Type 1 collagen, α-SMA, and this was accompanied by attenuated fibrosis-associated signaling. A DKT’s active ingredient Japanese Pepper increased the mRNA and protein expressions of TRPA1, which in turn negatively regulated collagen synthesis in InMyoFibs. In stenotic regions of CD patient’s intestines, TRPA1 expression was significantly increased. However, several limitations remain in this study that may compromise the value and relevance of this study, which include the inability of TNBS to create a severe phenotype of chronic colitis, the lack of control data from human healthy donors, and no comparative data from other Chinese (herbal) medicines that may have similar actions.

Research conclusions

DKT-induced expression and activation of TRPA1 could be important mechanisms for suppressing intestinal fibrosis, which would in part account for the reported beneficial actions of DKT on inflamed intestines. Thus, targeting myofibroblast TRPA1 may serve as a new and promising therapeutic strategy for fibrotic stenotic changes occurring in incurable chronic inflammatory bowel diseases such as CD and ulcerative colitis.

Research perspectives

Our findings not only provide a novel molecular target for the anti-fibrotic therapy of inflammatory bowel diseases in the future, but also a framework to reinterpret the unique theories of traditional Oriental medicine.