Bifidobacterium longum subsp. longum K5 alleviates inflammatory response and prevents intestinal barrier injury induced by LPS in vitro based on comparative genomics.

Excessive immune responses and intestinal barrier injury are leading causes of inflammatory bowel diseases (IBD). Previously, we demonstrated that B. longum subsp. longum K5 alleviated DSS-stimulated colitis in mice, while K15 could not. Here, we investigated both strains' underlying mechanisms regarding their anti-inflammatory and intestinal barrier protective capacities. We assessed the potential characters of two strains, anti-inflammation activities in the LPS-induced RAW 264.7 cell model, and intestinal epithelial barrier functions in the LPS-induced Caco-2 cell monolayers model. Results showed that B. longum subsp. longum K5 exhibited high inhibition against the adhesion of E. coli ATCC 25922 to HT-29 and acetic acid production. B. longum subsp. longum K5 (MOI 1:100) significantly decreased the pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) and inflammatory mediator ROS, NO level in LPS (1μg/mL) -induced RAW 264.7 cells. It also significantly increased TEER value and decreased paracellular permeability of Caco-2 cells stimulated by LPS. B. longum...