Polyporus Umbellatus polysaccharide ameliorates rheumatoid arthritis via inhibiting inflammation and regulating gut microbiota.

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease that can cause cartilage and bone damage as well as a disability. Polyporus Umbellatus polysaccharide (PUP) as a β-glucan exhibit remarkable anti-inflammatory activity. This study investigated the protective effects of PUP on RA using type II collagen-induced arthritis (CIA) mouse model. It was found that PUP successfully reduced bone loss, cartilage degradation, pannus development, joint edema, and synovial hyperplasia in CIA mice. Analysis of the anti-RA mechanisms indicated that PUP could inhibit the Wnt/β-catenin and NF-κB signaling pathway to alter the secretion of inflammatory mediators in the joint tissues and serum of CIA mice. Concurrently, PUP remodeled the abundance of gut microbiota, especially the abundance of several specific bacteria, such as Odoribacter, Alistipes, Cryptobacteroides, and Lactobacillus. These results indicated that PUP possessed the potential of ameliorating RA and its anti-RA bioactivity might be attributed to the inhibition of inflammatory response and regulation of gut microbiota.