A Combined Therapy of Brassica Rapa L. Polysaccharides and Dexamethasone in Regulation of Rheumatoid Arthritis and Gut Microbiome

The immunosuppressive effect of corticosteroids has been widely used in treating rheumatoid arthritis. However, the current treatments for limited clinical efficacy and adverse reactions remain unsatisfactory. The consumption of natural polysaccharides exerts multiple beneficial health effects by modulating gut microbiota, which is considered a nutritional approach to addressing metabolic disorders. This study investigated the combined effects of Brassica rapa L. polysaccharides (BP, gavage) and dexamethasone (Dex, injection) on collagen‐induced arthritis (CIA) in mice. As a novel immunotherapeutic strategy, the combined therapy showed an improved anti‐rheumatic effect and reversed the immunosuppression status of CIA mice. BP adjuvant played a key role in the combined therapy, significantly altering the gut microbiota, inflammation, and gut barrier disruption in RA. These effects were largely associated with the recovered intestinal barrier function and homeostasis of the gut microbiota such as Muribaculaceae and Candidatus_Saccharimonas . Simultaneously, BP promoted the complex interplay between host immune function and gut microbiota by altering the metabolic profile, particularly amino acid and lipid metabolism. Overall, the combined therapy of BP and Dex demonstrated the synergistic effect in anti‐rheumatoid and immunological efficacy by modulating the intestinal gut barrier function and microbiota.