Daphnetin extracted from Daphne odora Var. marginata contains
coumarin compounds, which possess properties of
analgesic and anti-inflammatory effects. In this study, we investigated the
therapeutic effect of
daphnetin on anti-
arthritis and its role on the balance of Tregs and Th17, using a
collagen-induced arthritis rat model.
Collagen-induced arthritis rats were treated with
daphnetin for 21 days. The
therapeutic effects of
daphnetin were evaluated by clinical symptoms and histopathology. The levels of Th17-, Treg-, Th2-, Th1-type
cytokines in serum were determined by ELISA. The expression levels of related receptors RORγt, NF-κB, Foxp3 and CD77 in joint tissues were detected by immunohistochemistry. Our results showed that administration of
daphnetin significantly alleviated the severity of the
arthritis, as evidenced by the reduction of
arthritis scores, suppression of the infiltration of inflammatory cells and prevention of synovial
hyperplasia, thereby resulting in the joint destruction in the
arthritis rats. Additionally,
daphnetin treatment reduced the serum level of Th17-, Th2- and Th1-type in
collagen-induced arthritis rats. Correspondingly, the expression of RORγt, NF-κB and CD77 in joint tissue of
collagen-induced arthritis rats was remarkably decreased, while the expression of Foxp3 and
IL-10 was remarkably increased after being administered with
daphnetin. Collectively, this study demonstrated that administration of
daphnetin attenuated the clinical symptoms and pathological destruction of
arthritis joints. The
therapeutic effects were associated with the up-regulation of Tregs, down-regulation of Th17-, Th2- and Th1-type cell responses. The results provide novel evidence that
daphnetin has
therapeutic effects on autoimmune
arthritis through modulating the balance of Tregs and Th17.