Artocarpus tonkinensis protects mice against collagen-induced arthritis and decreases Th17 cell function

Artocarpus tonkinensis (Moraceae) is a tree that grows in north Vietnam whose leafdecoction is used as a traditional re;medy by the Hmong ethnic group to treat arthritisand backache. Our study evaluated the decoction’s efficacy and mechanism of actionin DBA/1J mice with collagen-induced arthritis (CIA). Mice treated with the decoction(At) either from the first collagen immunization or after CIA development experiencedsignificantly less joint edema and inflammatory infiltration, whereas CIA-induced cartilagedamage could only be prevented by early At treatment. Autoimmune gene expressionprofiles showed that Th17 cell-associated chemokine CCL20 and cytokines IL-6, IL-17, and IL-22 were strongly downregulated by At. Reduced expression of IL-2, IL-17,IL-22, and FasL in lymph node cells from At-treated mice was further confirmed byreal-time PCR. The decoction also inhibited polarization of Th17 cells from CD4Csplenic T cells according to levels of IL-17 and RORC, a Th17 cell-specific transcriptionfactor. Chromatographic analysis identified At’s major component as maesopsin-b-D-glucoside, which could inhibit in vitro differentiation of Th17 cells. The decoctionsignificantly alleviated the signs and symptoms of CIA and inhibited the developmentand function of Th17 cells, highlighting its potent anti-inflammatory activity.