Administering Lactobacillus helveticus H9 Alleviates Dextran Sodium Sulfate-Induced Colitis in Rats

Inflammatory bowel disease (IBD) is a chronic non-specific gut inflammatory disease. Conventional treatments are insufficient to support long-term disease remission, so there is an urgent need to search for new IBD treatment options. This study evaluated the alleviation effect of Lactobacillus (L.) helveticus H9 on dextran sodium sulfate (DSS)-induced colitis rats. We found that administering L. helveticus H9 significantly reduced DAI (disease activity index) scores (p ≤ 0.05), spleen weights (p ≤ 0.05), and colonic tissue damage in the colitis rats, while increasing the body weight gain rate. Compared with the DSS group, L. helveticus H9-receiving rats had less serum tumor necrosis factor-α (p ≤ 0.05) and interleukin-1β (p < 0.01), a higher gut microbiota diversity, and significantly more Alistipes senegalensis (p ≤ 0.05) and Parabacteroides distasonis (p < 0.01). On the metabolomics level, 65 significantly differential metabolites (VIP > 1, p < 0.05, fold change > 2 or <0.5) were identified between the probiotic and DSS groups. Some significantly enriched pathways were identified in the fecal metabolome of the probiotic group, including Sphingolipid metabolism, Linoleic acid metabolism, alpha-Linolenic acid metabolism, Arachidonic acid metabolism, Glycerophospholipid metabolism, Pyrimidine metabolism, Tryptophan metabolism, Fatty acid biosynthesis and Steroid hormone biosynthesis metabolic pathways, and lecithin is an important differential metabolite interconnecting several of the enriched pathways. In summary, administering L. helveticus H9 modulated the gut microbiota, metabolome, and host immune response, which could relate to symptom alleviation in the colitis rats. Our study provides interesting data regarding the use of probiotics in managing chronic colitis.