Immunomodulatory and neuroprotective mechanisms of Huangqi glycoprotein treatment in experimental autoimmune encephalomyelitis

Previous studies have shown that Huangqi glycoprotein (HQGP) has an anti-inflammatory effect in vitro, and suppressed experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis; however, the mechanism underlying its effect is largely unknown. In this manuscript we investigated the mechanisms by which HQGP protect mice from EAE. HQGP was extracted from Astragalus membranaceus and purified by anion-exchange and gel filtration chromatography. HQGP delayed disease onset, reduced disease severity and alleviated inflammation and demyelination in the central nervous system (CNS). Moreover, HQGP reduced the infiltration of pathogenic immune cells and increased the expression of microtubule-associated protein 2 (MAP-2) and neuronal nuclei (NeuN) in the CNS. HQGP treatment also reduced the expression of chemokines such as CCL2 and CCL5 and the production of tumor necrosis factor α (TNF-α), interleukin (IL)-1β, IL-6, but increased the level of IL-10. These results demonstrate that HQGP suppressed EAE development by modulating the immune system and the infiltration of leukocytes to the CNS as well as promoting axon and neural repair.