Steamed broccoli sprouts diet alleviates inflammatory bowel disease by increasing anti-inflammatory, antioxidant, and gut protective metabolites in an ulcerative colitis mouse model

Abstract

Background: Broccoli is a cruciferous vegetable rich in bioactive compounds that may be beneficial against inflammatory bowel disease. However, an in-depth annotation and understanding of the metabolites and microbial interactions associated with the broccoli sprouts diet is necessary. 

Methods: Specific pathogen-free C57BL/6 mice (male, 6 weeks old) were divided into four treatments: control diet; control diet with 2.5% DSS in water to induce symptoms of ulcerative colitis; 90% control diet plus 10% steamed broccoli sprouts; and 90% control diet/ 10% steamed broccoli sprouts plus 2.5% DSS in drinking water to induce symptoms. DSS treatment was cycled three times, with five days of DSS followed by a recovery period of five days. Mice continued their diets throughout the duration of the study. Fecal samples were collected on day 30 and frozen at -80℃ until metabolomic analysis. Liquid chromatography, conducted using high-resolution mass spectrometry (LC-HRMS) was performed using a Waters Synapt G2, time-of-flight (TOF) XEVO. The LCMS metadata was processed in MassLynx, Progenesis QI, mzMine, and Sirius tools. This included the use of built-in search engines to obtain retention time, mass charge ratio, molecular weight, peak intensity, metabolites name, and formula using several libraries.

Results: Over 3,000 fecal metabolites were abundant in the feces of mice, with diet being a significant factor of differentiation (+/- steamed broccoli sprouts) and ulcerative colitis (+/- 2.5% DSS) treatment methods. The steamed broccoli sprouts intervention significantly increased the concentrations of beneficial metabolites, such as sulforaphane, short-chain fatty acids, tryptophan, indoles, glutamic acid, and polyphenolic metabolites. A positive correlation with commensal bacteria, Bacteroides spp., Intestinimonas, Oscillibacter, and Lachnospiraceae was found in the gut's colon, colon, cecal, and jejunum regions, and jejunum regions. 

Novelty: This study used innovative metabolomic methods to identify dietary and microbial anti-inflammatory, antioxidant, prebiotic, and gut-protective metabolites associated with diets including steamed broccoli sprouts. The research concluded that the diet was effective against ulcerative colitis in mice. 

Conclusions: These data suggest that broccoli sprouts may positively affect metabolites and microbial interactions. These benefits include their antioxidant, anti-inflammatory, and gut-protective properties that help with inflammatory bowel disease symptoms.  

Keywords: cruciferous vegetables, sulforaphane, glucoraphanin, gut microbiota, dietary bioactives, metabolomics, ulcerative colitis model