Functional study of chitosan oligosaccharide in ameliorating colitis in rats

Chitosan oligosaccharide (COS), a low-polymerization polymer derived from the breakdown of chitosan, possesses anti-oxidant, anti-cancer, anti-inflammatory, and blood glucose and lipid-regulating properties. The purpose of this study is to investigate the protective effect and mechanism of COS on the function of the intestinal barrier in rats with DSS-induced colitis, focusing on its regulation of the intestinal immunological barrier and mechanical barrier. The findings demonstrated that COS can not only lower the disease activity index (DAI) and ameliorate the loss of body weight in rats with colitis, but also raise the tight junction protein expression while decreasing intestinal fatty acid binding protein and diamine oxidase levels. However, DSS-induced colitis resulted in significant inflammatory infiltration (CD68 + macrophages and CD177 + neutrophils). COS ameliorated intestinal inflammation by reducing the expression of intestinal inflammatory cytokines IL-1β, IL-6, and TNF-α. These results indicate that COS effectively decreased the levels of inflammatory factors and inflammatory cell infiltration. Furthermore, with the alleviation of intestinal inflammation, the expression of inflammation-associated enzymes—prostaglandin-endoperoxide synthase 2 (PTGS2), nitric oxide synthase 2 (NOS2), and myeloperoxidase (MPO)—was significantly downregulated, accompanied by a marked reduction in their catalyzed inflammatory mediators, such as prostaglandin E2 (PGE2), a downstream product of PTGS2. Collectively, this study demonstrate that COS effectively preserve the structural integrity of intestinal tissue by alleviating DSS-induced intestinal inflammatory responses and maintaining the stability of intestinal barrier permeability. It significantly reduces the DAI of rats. These results suggest that COS holds potential as a dietary supplement for the management of inflammatory bowel disease. • DSS-induced colitis model for studying Chitosan oligosaccharide protection • Chitosan oligosaccharide reduces inflammation and preserves intestinal barrier integrity • Inhibits prostaglandin-endoperoxide synthase 2, nitric oxide synthase 2, myeloperoxidase and cytokine expression • Chitosan oligosaccharide as a potential dietary supplement for colitis management