Plant-derived polysaccharides, such as Atractylodes lancea rhizome polysaccharide (ALP), are good immune regulators. However, the immune regulatory mechanism of the ALP is unknown. This study aimed to evaluate the effects of ALP on the intestinal mucosal barrier and intestinal mucosal immunity of immunosuppressed mice. We also compared the activity of raw Atractylodes lancea rhizome polysaccharide (SALP) with wheat bran processed bran-fried Atractylodes lancea rhizome polysaccharide (FALP; both at 1.2 g/kg/d for mice). Our results showed that ALP effectively increased the immune organ index and blood cell count, stimulated the secretion of cytokines, and promoted the expression of occludin and zonula occludens-1 (ZO-1). ALP also promoted the expression of T cells and the secretion of sIgA. Furthermore, ALP alleviated the gut microbiota disorder in Cy-treated mice and increased the relative abundances of Lactobacillus and Faecalibaculum. ALP reversed the decrease in the level of SCFAs and promoted the expression of G protein-coupled receptor 43 (GPR43). To our knowledge, this study was the first to explore how the ALP protects the intestinal mucosal barrier and enhances intestinal mucosal immunity by alleviating the gut microbiota imbalance and metabolic disorders of SCFAs. FALP was more therapeutic than SALP, suggesting that FALP could be developed as a promising functional food component.
Keywords: Atractylodes lancea rhizome polysaccharide; gut microbiota; immunosuppressed; intestinal mucosal immunity; short-chain fatty acids.