Basic Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jan 21, 2018; 24(3): 338-350
Published online Jan 21, 2018. doi: 10.3748/wjg.v24.i3.338
Effect of Lactobacillus rhamnosus GG supernatant on serotonin transporter expression in rats with post-infectious irritable bowel syndrome
Ya-Nan Cao, Li-Juan Feng, Yuan-Yuan Liu, Kui Jiang, Mao-Jun Zhang, Yi-Xin Gu, Bang-Mao Wang, Jia Gao, Ze-Lan Wang, Yu-Ming Wang
Ya-Nan Cao, Yuan-Yuan Liu, Kui Jiang, Bang-Mao Wang, Jia Gao, Ze-Lan Wang, Yu-Ming Wang, Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin 300052, China
Li-Juan Feng, Department of Functional Division, Xingtai People’s Hospital, Xingtai 054031, Hebei Province, China
Mao-Jun Zhang, Yi-Xin Gu, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
Author contributions: Cao YN and Feng LJ contributed to essential research and statistical analysis; Wang YM, Jiang K, and Wang BM designed the study; Zhang MJ, Gu YX and Liu YY were mainly responsible for cultivation of bacteria, Gao J, Liu YY and Wang ZL contributed to raising animals; Cao YN and Feng LJ edited the article; Wang YM supported the financial arrangement.
Supported by the National Natural Science Foundation of China, No. 81570489.
Institutional review board statement: This study was approved by the Tianjin Medical University General Hospital.
Institutional animal care and use committee statement: All procedures involving animals were reviewed and approved by the Animal Ethics and Welfare Committee of Tianjin Medical University.
Conflict-of-interest statement: The authors declare that they have no competing interests.
Data sharing statement: Readers can get the data of this paper by contacting us via E-mail: ywang12@tmu.edu.cn.
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: Yu-Ming Wang, MD, PhD, Attending Physician, Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, No. 154, Anshan Road, Heping District, Tianjin 300052, China. ywang12@tmu.edu.cn
Telephone: +86-22-60362608 Fax: +86-22-60363768
Received: November 9, 2017
Peer-review started: November 9, 2017
First decision: November 30, 2017
Revised: December 6, 2017
Accepted: December 12, 2017
Article in press: December 12, 2017
Published online: January 21, 2018
Abstract
AIM

To evaluate the effect of Lactobacillus rhamnosus GG supernatant (LGG-s) on the expression of serotonin transporter (SERT) in rats with post-infectious irritable bowel syndrome (PI-IBS).

METHODS

Campylobacter jejuni 81-176 (1010 CFU/mL) was used to induce intestinal infection to develop a PI-IBS model. After evaluation of the post-infectious phase by biochemical tests, DNA agarose gel electrophoresis, abdominal withdrawal reflex (AWR) test, and the intestinal motility test, four PI-IBS groups received different concentrations of LGG-s for 4 wk. The treatments were maintained for 1.0, 2.0, 3.0 or 4.0 wk during the experiment, and the colons and brains were removed for later use each week. SERT mRNA and protein levels were detected by real-time PCR and Western blot, respectively.

RESULTS

The levels of SERT mRNA and protein in intestinal tissue were higher in rats treated with LGG-s than in control rats and PI-IBS rats gavaged with PBS during the whole study. Undiluted LGG-s up-regulated SERT mRNA level by 2.67 times compared with the control group by week 2, and SERT mRNA expression kept increasing later. Double-diluted LGG-s was similar to undiluted-LGG-s, resulting in high levels of SERT mRNA. Triple-diluted LGG-s up-regulated SERT mRNA expression level by 6.9-times compared with the control group, but SERT mRNA expression decreased rapidly at the end of the second week. At the first week, SERT protein levels were basically comparable in rats treated with undiluted LGG-s, double-diluted LGG-s, and triple-diluted LGG-s, which were higher than those in the control group and PBS-treated PI-IBS group. SERT protein levels in the intestine were also comparable in rats treated with undiluted LGG-s, double-diluted LGG-s, and triple-diluted LGG-s by the second and third weeks. SERT mRNA and protein levels in the brain had no statistical difference in the groups during the experiment.

CONCLUSION

LGG-s can up-regulate SERT mRNA and protein levels in intestinal tissue but has no influence in brain tissue in rats with PI-IBS.

Keywords: Serotonin transporter, Intestinal infection, Lactobacillus rhamnosus supernatant, Irritable bowel syndrome

Core tip: There are few reports on the effect of the supernatant of Lactobacillus rhamnosus GG (LGG) on serotonin transporter (SERT) expression in rats with post-infectious irritable bowel syndrome (PI-IBS). An experimental rat model of PI-IBS was developed by Campylobacter jejuni infection. SERT levels in intestinal and brain tissues were detected to evaluate the effect of LGG-s.