Crataegus pinnatifida polysaccharide alleviates DSS-induced colitis in mice by regulating the intestinal microbiota and enhancing arginine biosynthesis.

BACKGROUND

The development of effective and safe dietary supplements is essential for both the prevention and management of ulcerative colitis (UC), as its pathogenesis is intricate and difficult to completely resolve. Crataegus pinnatifida, a medicinal food with a long history of use, has broad medicinal value. Recent research has revealed promising insights into the role of polysaccharide derived from Crataegus pinnatifida on modulating short-chain fatty acids (SCFAs) to alleviate UC inflammation. However, the mechanisms by which CPP regulates the intestinal microbiota and key metabolites during the antagonistic phase of UC have yet to be elucidated.

OBJECTIVE

This research elucidated the protective role of CPP in relation to UC, highlighted the mechanisms through which CPP operates, particularly regarding gut microbiota and metabolism, and offered a theoretical foundation for the potential use of CPP as a dietary supplement aimed at preventing UC.

METHODS

The impact of CPP on acute UC induced by 3 % DSS in mice was examined through the evaluation of the disease activity index, measurement of colon length, and observation of body weight changes. Enzyme-linked immunosorbent assay (ELISA) was used to measure inflammatory factor levels in both serum and colon, as well as to assess oxidative stress mediators. The intestinal histological damage, mucus layer damage and the level of tight junction protein were analyzed by histopathological staining and western blot (WB). The impact of gut microbiota on CPP in colitis was evaluated using 16S rRNA sequencing, microbiota depletion experiments, and fecal microbiota transplantation (FMT) studies. The key metabolic pathways and key metabolites affected by CPP in the treatment of UC were analyzed through untargeted metabolomics sequencing, ELISA, and WB assays.

RESULTS

Prophylactic dietary supplementation with Crataegus pinnatifida polysaccharide (CPP) notably reduced the fundamental clinical manifestations of UC induced by DSS, including DAI score, reduced colon length, and weight loss, as well as inflammation and oxidative stress. CPP promoted the expression of Claudin-1, ZO-1 and Occludin and promoted mucin secretion, which contributed to the mitigation of intestinal barrier damage caused by DSS. 16S sequencing results and metabolomics results revealed that CPP intervention upregulated the relative abundance of Lactobacillus, thereby reshaping the intestinal microbiota and activate the arginine biosynthesis pathway. The results of fecal microbiota transplantation and antibiotic clearance experiments indicated that the alleviating effect of CPP on UC was dependent on the intestinal microbiota and this alleviating effect was transferred through fecal microbiota transplantation. Mechanistically, CPP indirectly promoted the expression of the rate-limiting enzyme argininosuccinate synthase 1 (ASS1) in the intestinal Arginine biosynthesis pathway by reshaping the intestinal microbiota, thereby increasing intestinal Arginine level and alleviating the inflammatory response and oxidative stress induced by DSS and intestinal barrier damage.

CONCLUSION

Our research findings demonstrate that CPP is a plant-derived polysaccharide that alleviates UC by modulating the gut microbiota and enhancing arginine biosynthesis.