Protective effects and mechanisms of extracts of Gleditsia sinensis Lam. Thorn on DSS-induced colitis in mice

Ethnopharmacological relevance: Inflammatory Bowel Disease (IBD), encompassing Ulcerative Colitis (UC) and Crohn's Disease (CD), stems from a multifaceted interaction of hereditary, immunological, ecological, and microbial elements. Current treatments have limitations, necessitating new therapeutic approaches.

Aim of the study: This study investigates the safeguarding impacts and fundamental processes of extracts of Gleditsia sinensis Lam. thorn (EGST) in a dextran sulfate sodium (DSS)-induced colitis model in mice.

Materials and methods: A total of 180g of dried EGST were prepared, and untargeted metabolomic profiling using high-resolution liquid chromatography electrospray ionization orbitrap mass spectrometry (HR-LC-ESI-Orbitrap-MS) identified 930 compounds. UC model mice were administered 3% DSS for 7 d, followed by EGST treatment. The analysis encompassed physiological and pathological evaluations, serum cytokine ELISA, gut microbiota (GM) metagenomic sequencing, GC-MS metabolomics, mRNA sequencing, and Western Blot.

Results: EGST markedly mitigated colitis symptoms, evidenced by reduced weight loss, lower DAI scores, and less colon shortening. It also decreased levels of pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) while boosting IL-10. Histological examination revealed diminished tissue damage, restoration of crypts, and reduced inflammation, with barrier integrity maintained via upregulation of occludin and ZO-1. Metagenomic sequencing demonstrated that EGST modulated the GM, enhancing the levels of Firmicutes and Bacteroidetes while reducing the levels of Proteobacteria and Verrucomicrobia. Metabolomic analysis indicated that EGST influenced critical pathways, including those involving D-amino acids, glutathione, cysteine, and methionine metabolism. Furthermore, mRNA sequencing identified 2625 differentially expressed genes (DEGs), comprising 1729 with increased and 896 with decreased expression, and highlighted EGST's impact on the PPARγ/AMPK/NF-κB pathway.

Conclusion: Overall, EGST mitigates DSS-induced colitis through modulation of GM, metabolic profiles, and gene expression, suggesting its promise as a naturally derived treatment for colitis.