Effects of chitosan oligosaccharides (COS) and FMT from COS-dosed mice on intestinal barrier function and cell apoptosis

Chitosan oligosaccharides (COS) show the potential to support the intestinal health, but the mechanism and role of COS-derived intestinal microbiota are unknown. We explored the protective effect of direct administration of COS on intestinal barrier function using an in vivo colitis mouse model and an in vitro enterotoxigenic Escherichia coli (ETEC)-challenged IPEC-J2 cell model. COS directly enhanced the intestinal barrier function. COS intervention also promoted the abundance and diversity of intestinal flora. Importantly, FMT intervention with a COS-derived microbiome decreased the disease index level and alleviated histopathological changes, and improved gut barrier function in the colitis model. Both COS and COS-derived microbiota suppressed ETEC-induced cellular apoptosis in IPEC-J2 cells. This study firstly confirms transplantation of COS-modified fecal microbiota can enhance the intestinal barrier function. The mechanism underlying COS benefits is due to a direct intervention by COS supplementation and an indirect improvement of the gut microbiota induced by COS exposure.