Original Article
Copyright ©2014 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Apr 28, 2014; 20(16): 4636-4647
Published online Apr 28, 2014. doi: 10.3748/wjg.v20.i16.4636
Combined probiotic bacteria promotes intestinal epithelial barrier function in interleukin-10-gene-deficient mice
Chen-Zhang Shi, Hong-Qi Chen, Yong Liang, Yang Xia, Yong-Zhi Yang, Jun Yang, Jun-Dong Zhang, Shu-Hai Wang, Jing Liu, Huan-Long Qin
Chen-Zhang Shi, Hong-Qi Chen, Yong Liang, Yang Xia, Yong-Zhi Yang, Jun Yang, Huan-Long Qin, Department of Surgery, Affiliated Sixth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai 200233, China
Jun-Dong Zhang, Shu-Hai Wang, Jing Liu, Sine institute of Materia Medica, Shanghai Sine Pharmaceutical Co., Ltd, Shanghai 201206, China
Author contributions: Shi CZ, Chen HQ, Qin HL conceived and designed the study; Shi CZ, Chen HQ, Liang Y, Xia Y and Yang YZ performed the experiments; Shi CZ, Chen HQ, Liang Y and Qin HL analyzed the data; Shi CZ, Chen HQ, Liang Y and Qin HL, drafted the article or revised it critically for important intellectual content; Shi CZ and Qin HL wrote the paper; and all authors have read and approved the final version to be published.
Supported by The National Natural Science Foundation Key Projects of China, No. 81230057; National Natural Science Foundation of China, No. 81172325; and The Major Basic Research Program of Shanghai, No. 12DZ1930502
Correspondence to: Huan-Long Qin, MD, Professor, Department of Surgery, Affiliated Sixth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, 600 Yishan Road, Shanghai 200233, China. hlqin10@163.com
Telephone: +86-21-64361349 Fax: +86-21-64368920
Received: October 16, 2013
Revised: November 29, 2013
Accepted: January 2, 2014
Published online: April 28, 2014
Processing time: 194 Days and 10.1 Hours
Abstract

AIM: To investigate the protective effects of combinations of probiotic (Bifico) on interleukin (IL)-10-gene-deficient (IL-10 KO) mice and Caco-2 cell monolayers.

METHODS: IL-10 KO mice were used to assess the benefits of Bifico in vivo. IL-10 KO and control mice received approximately 1.5 × 108 cfu/d of Bifico for 4 wk. Colons were then removed and analyzed for epithelial barrier function by Ussing Chamber, while an ELISA was used to evaluate proinflammatory cytokines. The colon epithelial cell line, Caco-2, was used to test the benefit of Bifico in vitro. Enteroinvasive Escherichia coli (EIEC) and the probiotic mixture Bifico, or single probiotic strains, were applied to cultured Caco-2 monolayers. Barrier function was determined by measuring transepithelial electrical resistance and tight junction protein expression.

RESULTS: Treatment of IL-10 KO mice with Bifico partially restored body weight, colon length, and epithelial barrier integrity to wild-type levels. In addition, IL-10 KO mice receiving Bifico treatment had reduced mucosal secretion of tumor necrosis factor-α and interferon-γ, and attenuated colonic disease. Moreover, treatment of Caco-2 monolayers with Bifico or single-strain probiotics in vitro inhibited EIEC invasion and reduced the secretion of proinflammatory cytokines.

CONCLUSION: Bifico reduced colon inflammation in IL-10 KO mice, and promoted and improved epithelial-barrier function, enhanced resistance to EIEC invasion, and decreased proinflammatory cytokine secretion.

Keywords: Probiotic bacteria; Intestinal barrier function; Tight junction proteins; Interleukin-10 gene-deficient mice; Caco-2 monolayers

Core tip: We investigated the protective effects of combinations of probiotic bacteria (Bifico) on interleukin (IL)-10 gene-deficient (IL-10 KO) mice and Caco-2 cell monolayers. Treatment of IL-10 KO mice with Bifico partially restored body weight, colon length, and epithelial barrier integrity to wild-type levels. Treatment of Caco-2 monolayers with Bifico or single-strain probiotics inhibited enteroinvasive Escherichia coli (EIEC) invasion and reduced secretion of proinflammatory cytokines. Oral administration of Bifico reduced colon inflammation, and directly promoted epithelial barrier function. In addition, Bifico improved epithelial barrier function, and enhanced resistance to EIEC invasion in vitro.