Basic Study
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jun 21, 2019; 25(23): 2924-2934
Published online Jun 21, 2019. doi: 10.3748/wjg.v25.i23.2924
Effects of Bifidobacterium infantis on cytokine-induced neutrophil chemoattractant and insulin-like growth factor-1 in the ileum of rats with endotoxin injury
Wei Wang, Mei Sun, Yu-Ling Zheng, Liu-Yu Sun, Shu-Qiang Qu
Wei Wang, Yu-Ling Zheng, Liu-Yu Sun, Shu-Qiang Qu, Department of Pediatrics, The Second Affiliated Hospital of Harbin Medical University, Harbin 150086, Heilongjiang Province, China
Mei Sun, Department of Pediatric Gastroenterology, Shengjing Hospital of China Medical University, Shenyang 110004, Liaoning Province, China
Author contributions: Wang W and Sun M designed the experiment; all authors took part in this experiment; Zheng Y collected the data; Sun L performed analysis of the data; all authors participated in writing and critical revision of the manuscript; Qu S provided final approval of the manuscript.
Supported by the Education Department of Heilongjiang Province, China, No. 11521124.
Institutional review board statement: This study was approved by the Institutional Review Board of the Second Affiliated Hospital of Harbin Medical University.
Institutional animal care and use committee statement: This study was approved by the Institutional Animal Ethical Review Board of the Second Affiliated Hospital of Harbin Medical University (SYDW2018-115).
Conflict-of-interest statement: No conflict of interest exists.
Data sharing statement: No additional data sharing.
ARRIVE guidelines statement: The ARRIVE Guidelines have been adopted.
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/
Corresponding author: Shu-Qiang Qu, PhD, Chief Doctor, Director, Professor, Teacher, Pediatrician, Department of Pediatrics, The Second Affiliated Hospital of Harbin Medical University, No. 246 Xuefu Road, Harbin 150086, Heilongjiang Province, China. qushuqiang1962@hotmail.com
Telephone: +86-451-86297730 Fax: +86-451-86297730
Received: November 21, 2018
Peer-review started: November 22, 2018
First decision: December 12, 2018
Revised: March 12, 2019
Accepted: March 29, 2019
Article in press: March 30, 2019
Published online: June 21, 2019
Abstract
BACKGROUND

The digestive tract is the maximal immunizing tissue in the body, and mucosal integrity and functional status of the gut is very important to maintain a healthy organism. Severe infection is one of the most common causes of gastrointestinal dysfunction, and the pathogenesis is closely related to endotoxemia and intestinal barrier injury. Bifidobacterium is one of the main probiotics in the human body that is involved in digestion, absorption, metabolism, nutrition, and immunity. Bifidobacterium plays an important role in maintaining the intestinal mucosal barrier integrity. This study investigated the protective mechanism of Bifidobacterium during ileal injury in rats.

AIM

To investigate the effects of Bifidobacterium on cytokine-induced neutrophil chemoattractant (CINC) and insulin-like growth factor 1 (IGF-1) in the ileum of rats with endotoxin injury.

METHODS

Preweaning rats were randomly divided into three groups: Control (group C), model (group E) and treatment (group T). Group E was intraperitoneally injected with lipopolysaccharide (LPS) to create an animal model of intestinal injury. Group T was intragastrically administered Bifidobacterium suspension 7 d before LPS. Group C was intraperitoneally injected with normal saline. The rats were killed at 2, 6 or 12 h after LPS or physiological saline injection to collect ileal tissue samples. The expression of ileal CINC mRNA was evaluated by reverse transcription-polymerase chain reaction (RT-PCR), and expression of ileal IGF-1 protein and mRNA was detected by immunohistochemistry and RT-PCR, respectively.

RESULTS

The ileum of rats in Group C did not express CINC mRNA, ileums from Group E expressed high levels, which was then significantly decreased in Group T (F = 23.947, P < 0.05). There was no significant difference in CINC mRNA expression at different times (F = 0.665, P > 0.05). There was a high level of IGF-1 brown granules in ileal crypts and epithelial cells in Group C, sparse staining in Group E, and dark, dense brown staining in Group T. There was a significant difference between Groups C and E and Groups E and T (P < 0.05). There was no significant difference in IGF-1 protein expression at different times (F = 1.269, P > 0.05). IGF-1 mRNA expression was significantly different among the three groups (P < 0.05), though not at different times (F = 0.086, P > 0.05).

CONCLUSION

Expression of CINC mRNA increased in the ileum of preweaning rats with endotoxin injury, and exogenous administration of Bifidobacterium reduced CINC mRNA expression. IGF-1 protein and mRNA expression decreased in the ileum of preweaning rats with endotoxin injury, and exogenous administration of Bifidobacterium prevented the decrease in IGF-1 expression. Bifidobacterium may increase IGF-1 expression and enhance intestinal immune barrier function in rats with endotoxin injury.

Keywords: Bifidobacterium, Ileum, Cytokine-induced neutrophil chemoattractant, Insulin-like growth factor-1, Rats

Core tip: The purpose of this article is to investigate the effects of Bifidobacterium on cytokine-induced neutrophil chemoattractant and insulin-like growth factor 1 (IGF-1) in the ileum of rats with endotoxin injury. It was found that Bifidobacterium may increase IGF-1 expression and enhance intestinal immune barrier function in rats with endotoxin injury.