Effects of the acid polysaccharide fraction isolated from a cultivated Cordyceps sinensis on macrophages in vitro

The acid polysaccharide fraction (APSF) extracted from the mycelia of cultivated Cordyceps sinensis is water-soluble polysaccharide. In this study we evaluated the modulating effects of APSF on murine macrophage cell line RAW264.7. Phagocytotic assay by neutral red and FITC-dextran internalization showed that APSF stimulated the phagocytosis of macrophages. The nitrite levels in the culture supernatant determined using Griess reagent revealed the elevation of NO production after treatment with APSF. RT-PCR and immunocytochemistry assay indicated that APSF promoted both the mRNA and protein expressions of inducible nitric oxide synthase (iNOS). Furthermore, Western blotting demonstrated that NF-κB levels in nucleuses increased after APSF treatment, suggesting that APSF probably stimulated macrophage activities by activating the IκB-NF-κB pathway.