A Study On Immunomodulatory Mechanism Of Astragalus Polysaccharide And Polysaccharopeptide Mediated By Ca²⁺-cAMP Signaling Pathway

Objective: to study the effect of Astragalus polysaccharide（APS） and Polysaccharopeptide（PSP） on the second messenger level of macrophages.Methods: in vitro, we treat macrophage RAW 264.7 with APS, PSP and LPS, after incubating for several hours, we detected intracellular PKC by power-spectral method and detected intracellular cAMP, DAG, IP3 concentration by ELISA. Then the intracellular calcium fluorescence value of macrophage RAW264.7 with APS, PSP and NiCl2 were detected by confocal laser scanning; and real-time fluorescence quantitative PCR（Q-PCR） was used to quantitative analysis the mRNA expression of NF-κB in RAW treated APS and PSP with or without NiCl2, and Western blot was used to detect the protein expression of NF-κB.Results: the APS and PSP can significantly incease the concentrations of intracellular second messengers( NO, cAMP, DAG, IP3, Ca²⁺) in macrophage（P<0.05）; After treated with APS and PSP, the gene and protein levels of NF-κB were significantly higher than that in control group（P<0.05）, the gene and protein levels of NF-κB were decreased significantly after the treatment of NiCl2（P<0.05）.Conclusion: These data strongly suggest Ca²⁺-cAMP signaling pathway is partly involved in APS and PSP mediated immunomodulatory activities.