Spatial Localization and Binding of the Probiotic Lactobacillus farciminis to the Rat Intestinal Mucosa: Influence of Chronic Stress.

Stéphanie Da Silva,Myriam Mercade-Loubière,Afifa Ait-Belgnaoui,Bélinda Ringot,Christel Salvador-Cartier,Catherine Robbe-Masselot,Isabelle Fourquaux,Muriel Mercier-Bonin,Pascal Loubière,Arthur Raymond,Vassilia Théodorou,Renaud Léonard

doi:10.1371/journal.pone.0136048

Abstract

The present study aimed at detecting the exogenously applied probiotic Lactobacillus farciminis in rats, after exposure to IBS-like chronic stress, based on 4-day Water Avoidance Stress (WAS). The presence of L. farciminis in both ileal and colonic mucosal tissues was demonstrated by FISH and qPCR, with ileum as the preferential niche, as for the SFB population. A different spatial distribution of the probiotic was observed: in the ileum, bacteria were organized in micro-colonies more or less close to the epithelium whereas, in the colon, they were mainly visualized far away from the epithelium. When rats were submitted to WAS, the L. farciminis population substantially decreased in both intestinal regions, due to a stress-induced increase in colonic motility and defecation, rather than a modification of bacterial binding to the intestinal mucin Muc2.

Highlights

The human intestine is colonized with a complex microbial community, known as the microbiota, which reaches about 1014 bacteria and consists of at least 1000 species
FISH with a universal probe was used to visualize the spatial organization of bacterial communities in mucosal tissues
In the ileum, dispersed cells were observed in the lumen but closer or even in direct contact with the epithelium, bacteria mainly exhibited a typical long filamentous shape with segments (Fig 1A), probably corresponding to Segmented Filamentous Bacteria (SFB)

Summary

Introduction

The human intestine is colonized with a complex microbial community, known as the microbiota, which reaches about 1014 bacteria and consists of at least 1000 species. This microbiota plays a key role in gut physiology and host health by fulfilling a great number of functions, such as digestion of otherwise unprocessed dietary nutrients, synthesis of vitamins and shortchain fatty acids, modulation of the immune system and inhibition of pathogen colonization. Chronic Stress and Intestinal Localization of Lactobacillus farciminis preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.

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Conclusion