Astagalus Polysaccharide Attenuates Murine Colitis through Inhibiton of the NLRP3 Inflammasome

Astragalus polysaccharide is an important bioactive component of Astragalus membranaceus, an herb used in traditional Chinese medicine for treating inflammatory bowel disease. The NOD-like receptor protein 3 inflammasome plays an important role in the pathogenesis of inflammatory bowel disease. However, little is known about the role of NOD-like receptor protein 3 inflammasome in Astragalus polysaccharide-treated mice with experimental colitis. For this study, we investigated the molecular mechanisms that underlie the treatment of inflammatory bowel disease by Astragalus polysaccharide. We show that Astragalus polysaccharide treatment reduces the disease activity index and histological injury scores compared to the colitis model group. Astragalus polysaccharide also effectively inhibited the expression of NOD-like receptor protein 3, apoptotic speck protein containing a c-terminal caspase recruitment domain, caspase-1, interleukin-18, and interleukin-1β, as shown by quantificational RT-PCR or the enzyme-linked immunosorbent assay. Furthermore, Astragalus polysaccharide treatments produced significant dose-dependent improvements in dextran sulfate sodium-induced experimental colitis. Our data provide the reliable evidence that Astragalus polysaccharide is able to exert a therapeutic effect in dextran sulfate sodium-induced colitis by inhibiting the activation of the NOD-like receptor protein 3 inflammasome, which acts to decrease the production of inflammatory factors such as interleukin-18 and interleukin-1β.