Therapeutic effect of dioscin on collagen-induced arthritis through reduction of Th1/Th2

• The proportion of Th1/Th2 in the dioscin group was lower compared to the model group.
• p-STAT4 expression was decreased in the dioscin group than that in the model group.
• GATA3 expression was increased in the dioscin group compared to the model group.

The aim of this study was to detect the therapeutic effect of dioscin on collagen-induced arthritis (CIA). Mice model of CIA was induced by chicken collagen II and arthritis index was assessed. After suspension of dioscin (100 mg/kg/d) or triptolide was intragastrically administered, the left paw swelling and body weight of each mouse were measured. Then tissue samples were assayed by histopathological analysis. The levels of Th1 and Th2 were detected by flow cytometry. The expression of p-STAT1, p-STAT4 and p-STAT6 was demonstrated by western blot analysis, and T-bet and GATA-3 expression was detected by RT-PCR. The paw swelling and arthritis index were decreased and body weight was increased in the high dose of dioscin group compared to the model group (P < 0.05). Histopathological analysis revealed that the damage of synovium tissue in dioscin and triptolide group alleviated. The ratio of Th1/Th2 in the dioscin group (0.82 ± 0.24) and triptolide group (0.99 ± 0.44) was lower than that in the model group (1.84 ± 0.70, P < 0.05). Additionally, p-STAT4 expression was decreased, and both p-STAT6 and GATA3 expression was increased in the dioscin group than that in the model group (P < 0.05). Dioscin might have some therapeutic effects on CIA through regulating the proportion of Th1/Th2 cells, which could reduce the expression of p-STAT4, increase the expression of p-STAT6 and GATA3 in the synovial tissue.