Differential reinforcement of intestinal barrier function by various Lactobacillus reuteri strains in mice with DSS-induced acute colitis

Inflammatory bowel disease is a complex, refractory disorder characterised by chronic gastrointestinal inflammation. Studies have reported that Lactobacillus reuteri alleviates gastrointestinal inflammation and strengthens the intestinal barrier. However, further biochemical and genetic studies are required to correctly understand the therapeutic potential of L. reuteri.This study sought to further understand the anti-colitis effect of L. reuteri isolated from faecal samples of healthy locals by focusing on biochemical (immunological, mechanical, chemical and biological barriers) and genetic studies.In this study, we assessed and compared the benefits and efficacy of L. reuteri FYNDL13 and FCQHC8L in the treatment of colitis and found strain FYNDL13 to be superior to FCQHC8L in this regard. Compared with FCQHC8L, FYNDL13 was associated with more diverse and powerful regulatory pathways. Meanwhile, it encouraged butyric acid formation, upregulated antimicrobial peptide-coding gene transcription and prevented hyperimmune reactions on the intestinal periphery and within the intestine. Moreover, it enhanced the abundance of beneficial bacteria (Bifidobacterium, Akkermansia, Blautia and Oscillospira), thereby limiting the relative abundance of harmful bacteria (Bacteroides and Sutterella). Furthermore, the advantage might be attributed to metabolism- and defence system-related genomic characteristics.Taken together, our study compares and summarizes a pathway paradigm of these two L. reuteri strains in reinforcing the intestinal barrier against colitis and identifies candidate genes responsible for microbiota-immune axis balance.