Astragalus embranaceus extract activates immune response in macrophages via heparanase

Astragalus membranaceus (AM), a traditional Chinese medicinal herb, has immunoregulatory properties in many diseases. We investigated the effects and mechanism of Astragalus membranaceus extract (AME) in the macrophage migration and immune response mediator release. The viability of Ana-1 macrophages treated with AME was evaluated by the MTT method. The secretion and mRNA levels of IL-1β and TNF-a were measured by ELISA and RT-PCR, respectively. Macrophage migration was assayed by transwell assay. The activity of heparanase (HPA) was determined by a heparin-degrading enzyme assay. Our results didn't show any toxicity of AME in macrophages. AME increased the activity of HPA, cell migration, mRNA levels and secretion of IL-1β and TNF-a in macrophages. Pretreatment with anti-HPA antibody reduced cell migration, secretion of IL-1β and TNF-a did not change the mRNA levels of IL-1β and TNF-a significantly in AME-treated macrophages. This suggests that AME may increase the release of immune response mediator and cell migration via HPA to activate immune response in macrophages.