Effect of Heat-killed Lactobacillus casei DKGF7 on a Rat Model of Irritable Bowel Syndrome.

Gyeol Seong,Hong Seog Kim,Cheol-Hyun Kim,Seungbaek Lee,Dong Kyung Chang,Yeon Sil Jang,So-Young Park,Eui-Joong Kim,Yang Won Min

doi:10.3390/nu13020568

Gyeol Seong, Hong Seog Kim + Show 7 more

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https://doi.org/10.3390/nu13020568

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Abstract

Non-viable bacteria, referred to as “paraprobiotics,” have attracted attention as potentially safer alternatives to probiotics. The aim of this study was to investigate the efficacy of heat-killed Lactobacillus casei DKGF7 on the symptomatic improvement of irritable bowel syndrome (IBS) in a rat disease model and to elucidate the underlying mechanisms that contribute to the beneficial effects of heat-killed probiotics. Seven male Wistar rats were induced with IBS by restraint stress and administered heat-killed L. casei DKGF7 for four weeks and then compared with seven rats in the control group. Stool consistency measured four weeks after initial treatment was the primary outcome measure. To investigate the mechanism of action of the heat-killed bacteria on IBS, we measured serum corticosterone levels, inflammatory cytokines in colon tissue, and expression of tight junction proteins (TJPs) in the epithelium. The treatment group showed significantly better stool consistency scores than the control group at week 4, as well as at every measured time point (all p values < 0.05). The treatment group showed lower serum corticosterone levels, lower colonic inflammatory cytokine levels, and higher expression of TJPs compared with the control group. Paraprobiotics such as heat-killed L. casei DKGF7 can improve stool consistency in a rat IBS model, which may indicate a potential therapeutic strategy for IBS treatment.

Highlights

A growing body of evidence suggests that gut microbiota play a central role in intestinal diseases and human health [1]
This understanding is the basis for treatments, which attempt to maintain a healthy equilibrium between the gut microbiota and host immune response, one of which is the administration of probiotics
The treatment group administered with heat-killed L. casei DKGF7 showed better stool consistency scores than the control group at week 4 and throughout the study period

Summary

Introduction

A growing body of evidence suggests that gut microbiota play a central role in intestinal diseases and human health [1]. The pathophysiology is largely unknown, but recent advances indicate a clear connection between the gut microbiota and intestinal mucosa [4], complex gut–brain disorder [5,6], low-grade mucosal inflammation [7], immune reaction [8], and altered intestinal permeability [9]. This understanding is the basis for treatments, which attempt to maintain a healthy equilibrium between the gut microbiota and host immune response, one of which is the administration of probiotics. These products have been referred to as “inactivated probiotics” or “ghost probiotics,” but recently the term “paraprobiotics” was coined to describe non-viable or inactivated bacterial cells that, when administered, confer a benefit to the consumer [15]

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