Biofilm-state Bifidobacterium adolescentis Gr19 under dynamic culture system effectively alleviates intestinal barrier dysfunction

Probiotics can regulate gut microbes to maintain human health. However, the sensitivity of probiotics to environmental conditions reduces their bioavailability. In contrast, the formation of probiotic biofilm provides a natural physical barrier against external interference. Our previous study established a dynamic culture system of the biofilm-state Bifidobacterium adolescentis Gr19 (B-DC-B. adolescentis Gr19), forming higher density and more structurally stable biofilms, which enhanced its potential probiotic properties in vivo. Thus, the protective effect and mechanism of B-DC-B. adolescentis Gr19 on lipopolysaccharide (LPS)- induced intestinal barrier dysfunction were investigated in this study. The results showed that B-DC-B. adolescentis Gr19 not only had high resistance and adhesion activity, but also improved the intestinal barrier by increasing goblet cells and promoting the expression of tight junction (TJ)-related proteins. Moreover, B-DC-B. adolescentis Gr19 effectively attenuated intestinal barrier injury in Caco-2 cells by improving intestinal permeability and integrity. Remarkably, B-DC-B. adolescentis Gr19 enhanced expression of TJ proteins, restored localization of cytoskeleton and reduced intestinal inflammation by suppressing the Ras homolog family member A/Rho-associated coiled-coil-forming kinases/nuclear factor kappa B/myosin light chain kinase/myosin light chain (RhoA/ ROCK/NF-κB/MLCK/MLC) pathway. Therefore, B -DC-B. adolescentis Gr19 plays a key role in mitigating LPS-induced intestinal barrier dysfunction. Overall, the present study provides a theoretical basis for ameliorating intestinal barrier dysfunction and developing novel functional foods by using biofilm-state probiotics under dynamic culture.