Sulfated Cyclocarya paliurus polysaccharides improve immune function of immunosuppressed mice by modulating intestinal microbiota

The study was aimed to investigate the effect of Cyclocarya paliurus polysaccharides (CPP) and the sulfation derivative (S-CPP) on modulate intestinal mucosal immunity and intestinal microbiota in cyclophosphamide-induced mice. The results showed that CPP and S-CPP effectively alleviated intestinal villi injury, enhanced the contents of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in small intestinal tissue and serum, and upregulated IL-1β at gene levels, zonula occludens-1 (ZO-1), Occludin and Claudin-1 at gene and protein levels, thereby promoting the repair of intestinal mechanical barrier and enhancing intestinal mucosal immunity. Moreover, the beneficial modulation of CPP and S-CPP on the overall structure of intestinal microbiota was revealed by performing 16S ribosomal RNA (16S rRNA) sequencing. Sulfated modification could improve the protection of CPP on the intestinal barrier and the regulation of systemic immunity. S-CPP had a stronger potential to reduce the damage of cyclophosphamide (Cy) on immunity and intestinal microbiota.