Astragalus polysaccharide enhances the immune function of RAW264.7 macrophages via the NF-κB p65/MAPK signaling pathway.

Abstract

The aim of the present study was to investigate the immunoregulatory effects of Astragalus polysaccharide (APS) on RAW264.7 cells. The production of cytokines by RAW264.7 cells was analyzed using ELISA, while cell viability and optimal concentration of APS were assessed using the Cell Counting Kit-8 assay. In addition, the mRNA levels of IL-6, inducible nitric oxide synthase (iNOS) and TNF-α were determined by reverse transcription-quantitative PCR analysis. The levels of co-stimulatory molecules and cell cycle distribution were assessed by flow cytometry. Electrophoretic mobility shift assay was used to determine the effects of APS on p65 expression. Compared with controls, APS enhanced the production of NO, the gene expression of TNF-α, IL-6 and iNOS and the protein levels of phosphorylated p65, p38, Jun N-terminal kinase and extracellular signal regulated kinase in RAW264.7 cells, whereas these effects of APS were alleviated by pyrrolidine dithiocarbamate. The results of the present study indicated that the immunoregulatory effects of APS are mediated, at least in part, via the activation of the NF-κB p65/MAPK signaling pathway.