Lactobacillus reuteriAmeliorates Intestinal Inflammation and Modulates Gut Microbiota and Metabolic Disorders in Dextran Sulfate Sodium-Induced Colitis in Mice

Lactobacillus reuteri, a commensal intestinal bacteria, has various health benefits including the regulation of immunity and intestinal microbiota. We examined whetherL. reuteriI5007 could protect mice against colitis in ameliorating inflammation, modulating microbiota, and metabolic composition. In vitro, HT-29 cells were cultured withL. reuteriI5007 or lipopolysaccharide treatment under three different conditions, i.e., pre-, co- (simultaneous), and posttreatment. Pretreatment withL. reuteriI5007 effectively relieves inflammation in HT-29 cells challenged with lipopolysaccharide. In vivo, mice were givenL. reuteriI5007 by gavage throughout the study, starting one week prior to dextran sulfate sodium (DSS) treatment for one week followed by two days without DSS.L. reuteriI5007 improved DSS-induced colitis, which was confirmed by reduced weight loss, colon length shortening, and histopathological damage, restored the mucus layer, as well as reduced pro-inflammatory cytokines levels. Analysis of 16S rDNA sequences and metabolome demonstrates thatL. reuteriI5007 significantly alters colonic microbiota and metabolic structural and functional composition. Overall, the results demonstrate thatL. reuteriI5007 pretreatment could effectively alleviate intestinal inflammation by regulating immune responses and altering the composition of gut microbiota structure and function, as well as improving metabolic disorders in mice with colitis.