Lactobacillus rhamnosus EM1107 in goat milk matrix modulates intestinal inflammation involving NF-κB p65 and SOCs-1 in an acid-induced colitis model

Highlights

• Lactobacillus rhamnosus EM1107 in goat milk matrix modulates intestinal inflammation involving NF-κB p65 and SOCs-1.

• Decreases proinflammatory cytokine levels and myeloperoxidase and improves colonic oxidative stress in colonic tissue.

• The probiotic was effective in protecting the colonic cytoarchitecture.

• Down-regulation of COX-2, iNOS and MMP-9 and IL-17.

• Up-regulation of MUC-2 and ZO-1.

Abstract

Inflammatory Bowel Diseases (IBD) is characterized by a deregulated immune response. Probiotics are able to modulate the intestinal microbiota and regulating inflammatory responses. This study evaluated the effect of pretreatment of Lactobacillus rhamnosus EM1107, isolated (EM1107) or added to goat cheese (LRC), on acetic acid-induced colitis in rats. EM1107 or LRC had a protective effect on intestinal inflammation, with the improvement of disease activity index and macroscopic damage caused by inflammation. It also reduced myeloperoxidase, TNF-α, IL-1β colonic levels and improved oxidative stress. The histological evaluation confirmed the beneficial effect in colonic tissue preservation. Intestinal immunohistochemical analysis revealed down-regulation of IL-17, NF-κB p65, MMP-2, MMP-9, and iNOS expression, up-regulation of SOCs-1, ZO-1 and MUC-2, which are important intestinal mucosal barrier proteins. These results suggest that Lactobacillus rhamnosus EM1107 alone or added to goat cheese exerts a preventive effect against acetic acid-induced damage and may be an alternative to human IBD.

Introduction

Inflammatory bowel disease (IBD) is a common term that encompasses Crohn’s Disease and Ulcerative Colitis, and are autoimmune diseases that affect mucosal integrity, characterized by periods of active inflammation alternating with remission periods. Although its etiology is not yet fully understood, it is known that IBD is multifactorial involving genetic susceptibility, environmental factors, and intestinal dysbiosis. Immune system activation is characteristic of IBD, and is accompanied by producing a wide variety of non-specific inflammatory mediators, including cytokines, chemokines, growth factors, arachidonic acid metabolites (e.g. prostaglandins and leukotrienes) and the metabolites of reactive oxygen species such as nitric oxide (Kucharzik et al., 2006, Park et al., 2017).

The therapeutic strategy implemented for IBD is to induce and maintain disease remission, and patients need to take medications chronically due to the nature of the disease. The most commonly used drugs involve anti-inflammatories, corticosteroids, and immune system modulators, but they do not appear to be effective in all cases. Immunosuppressive and biological drugs such as azathioprine and tumor necrosis factor alpha (TNF-α) blockers, respectively, have been widely used as therapy for IBD (Neurath, 2017, Pithadia and Jain, 2011). Despite the proven efficacy of these pharmacological agents, they have several side effects in addition to the high cost (Bressler et al., 2015, Moura et al., 2015). Therefore, it is of great interest to study effective therapeutic alternatives in reducing the inflammatory symptoms, among which include probiotic bacteria (Derikx et al., 2016, Le and Yang, 2018, Saez-Lara et al., 2015, Seo et al., 2017).

Probiotics are defined as live micro-organisms that confer human health benefits when consumed in an adequate quantity (Food and Agriculture Organisation of the United Nations and WHO Working Group, 2002). The use of probiotics in IBD is mainly supported by the ability to modulate intestinal microbiota components, an important etiological factor of IBD (Amit-Romach et al., 2015, Budarf et al., 2009, Frolkis et al., 2013, Rodríguez-Nogales et al., 2018a). In addition to modulating the microbiota, other probiotic action mechanisms are associated with benefits in treating IBD such as improved barrier function, reduced mucosal permeability (Abraham, 2017, Madsen et al., 2001, Srutkova et al., 2015), or increased secretion of mucin by epithelial cells, immunoregulatory action with suppression of proinflammatory cytokines (Lim, Jang, Jeong, Han, & Kim, 2017) and inducing protective cytokines such as IL-10 and transforming growth factor beta (TGF-β) (Sahu et al., 2015, Thakur et al., 2016, Yan and Polk, 2002).

Several studies have demonstrated the beneficial effect of administering various probiotics, either isolated or included in a food matrix, in different animal IBD models, such as Dextran Sodium Sulfate (DSS)-induced colitis, 2,4,6-trinitrobenzene sulfonic acid (TNBS) or acetic acid. In general, reduced pro-inflammatory markers, improved oxidative stress due to IBD, reduced mucosal lesion and increased short-chain fatty acids production have been observed (Geier et al., 2007, Peran et al., 2006, Rodríguez-Nogales et al., 2018b). The association of probiotic with antibiotics has also been investigated, showing a synergistic effect with better recovery of intestinal damage and increased remission time (Garrido-Mesa et al., 2011).

Among bacteria considered probiotic, Bifidobacterium and Lactobacillus are the most extensively studied, given their proven antibacterial effect against pathogenic bacteria. In addition, different studies with Lactobacillus, as well as L. casei, L. rhamnosus, L. sakei, L. fermentum, and L. plantarum have demonstrated promising results for treating IBD patients, given the regulatory effect of inflammatory markers in an experimental IBD model (Chung et al., 2008, Le and Yang, 2018, Seo et al., 2017, Yokota et al., 2018).

The Lactobacillus rhamnosus EM1107 strain was selected among lactic acid bacteria isolates considering its performance in a series of in vitro tests regarding probiotic potential, technological properties, and safety. L. rhamnosus EM1107 showed remarkable resistance to gastrointestinal conditions simulated in vitro, exhibited beta-galactosidase and bile salt hydrolase activity, as well as good viability in acidified milk (dos Santos et al., 2015). Therefore, this study evaluated the effect of administrating isolated Lactobacillus rhamnosus EM1107 or added to goat’s cheese (coalho cheese) in an experimental model of intestinal inflammation induced by acetic acid for the first time.