Effect of Paecilomyces cicadae polysaccharide Pc0-1 on cyclophosphamide-induced immunosuppression and regulation of intestinal flora in mice

Abstract

Paecilomyces cicadae are rich in resources and have promising research value and applications. A neutral branched heteropolysaccharide Pc0-1 has been extracted from it in our laboratory previously, the structural features and in vitro activity were also characterized. On this basis, the present research intended to investigate the potential mechanism by which Pc0-1 ameliorated cyclophosphamide (Cy)-induced immunosuppression in mice. The results demonstrated that Pc0-1 could alleviate the atrophy of immune organs and restore the tissue structure of the ileum. Pc0-1 could also alleviate oxidative stress and inflammatory response through reducing the level of lipid peroxidation in serum and maintaining the balance of Th1 and Th2. Meanwhile, Pc0-1 was also able to activate the Nrf2- Keap1 signaling pathway and stabilize Nrf2 by decreasing Keap1 activity, thus promoting the role of NQO1 in maintaining redox stability and HO-1 in preventing inflammation. Furthermore, gut microbial sequencing indicated that Pc0-1 prevented the differential expansion of flora, increased the abundance of beneficial bacteria Lactobacillus and Lachnospiraceae_NK4A136_group, decreased the abundance of harmful bacteria Desulfovibrio and Alistipes, and promoted the production of short-chain fatty acids (SCFAs). All these results demonstrated that Pc0-1 could regulate Cy-induced immunosuppression and improve the structure of intestinal flora, providing some theoretical basis for the in-depth development and application of Pc0-1 as an immunomodulator.