Anti-inflammatory effect and mechanisms of Huangqi glycoprotein in treating experimental autoimmune encephalomyelitis

Huangqi glycoprotein (HQGP) is prepared from Astragalus membranaceus by ammonium sulfate precipitation. It was indicated that HQGP has an immunoregulatory effect. In this study, we established a chronic experimental autoimmune encephalomyelitis (EAE) model and observed the therapeutic effect and possible mechanisms of HQGP (intraperitoneally at 1 mg/kg/day) on EAE. The results showed that HQGP delayed onset and ameliorated severity of EAE, and reduced the infiltration and accumulation of pathogenic T cells in the central nerves system (CNS). HQGP also reduced the production of IL-6, IL-17 and TNF-alpha and increased the level of IL-10. However, the level of IFN-gamma production was also increased in HQGP-treated mice compared with EAE control mice. In brain, chemokines such as CCL2 and CCL5 were inhibited in HQGP-treated EAE compared with control mice. These results demonstrate that HQGP alleviates the pathogenesis of EAE possibly by suppressing the neuroinflammation and decreasing the secretion of chemokines and cell adhesion.