Phytosomal curcumin alleviates collagen-induced arthritis by downregulating Th17 and upregulating Treg cell responses in rats

Objective: To explore the effects of a nano-formulation of curcumin (phytosomal curcumin) on the clinical and pathological symptoms of collagen-induced arthritis (CIA) in rats. Methods: Forty male Wistar rats were immunized with an emulsion containing bovine type II collagen and incomplete Freund's adjuvant and then administered phytosomal curcumin post-immunization. Clinical symptoms and histological analysis of the synovial tissues were performed. The effect of phytosomal curcumin on Th17 and Treg parameters was also evaluated. Results: Phytosomal curcumin reduced the clinical severity and paw swelling in CIA-induced rats, which was accompanied by a reduction in the number of inflammatory cell infiltration in the synovial tissue. Additionally, treatment with phytosomal curcumin significantly inhibited CIA-associated mediators as well as increased the anti-inflammatory mediators in comparison to the control groups. Conclusions: Phytosomal curcumin could improve CIA autoimmune responses and can be considered a potential candidate for the treatment of rheumatoid arthritis.