Synergistic effects of Sargassum horneri polysaccharides and lactic acid bacteria in alleviating DSS-induced colitis and restoring gut homeostasis.

Inflammatory bowel disease (IBD), characterized by chronic intestinal inflammation and compromised gut barrier integrity, remains a significant challenge in clinical management. This study explored the synergistic potential of Sargassum horneri polysaccharides (SHCPs) and Lactobacillus plantarum (LAB) in alleviating DSS-induced colitis. SHCPs were characterized using FTIR and SEM in this study, and their structural features-including high sulfate content, molecular weight distribution, and glycosidic linkages-were previously elucidated in our earlier work, supporting their classification as bioactive sulfate-rich polysaccharides and suggesting structure-dependent functionality. In vitro experiments using Caco-2 cell models showed that SHCPs promoted LAB adhesion and, in combination, significantly reduced pro-inflammatory cytokine levels (IL-6, IL-1β, TNF-α, and PGE2), thereby mitigating DSS-induced inflammation. This effect correlated with improved microbiota-host interactions and was linked to restoration of tight junction proteins (ZO-1, Occludin), suppression of Claudin-2, and downregulation of iNOS and COX-2. In IBD-induced zebrafish models, the synergistic effects of SHCPs and LAB were further validated, as evidenced by enhanced gut barrier integrity, alleviation of dysbiosis, and restoration of intestinal length. These findings highlight the potential synergistic effects of SHCPs and LAB as a combinatorial strategy to regulate gut inflammation and enhancing epithelial barrier function, potentially offering new insights and therapeutic opportunities for IBD intervention.