Effect of diosgenin on T-helper 17 cells in mice with collagen-induced arthritis

Background: Diosgenin, obtained from Dioscorea nipponica Makino, possesses anti-inflammatory properties. Objective: The objective of this study is to explore the therapeutic effects of diosgenin against collagen-induced arthritis (CIA) in DBA/1J mice. Materials and Methods: The CIA model was established using chicken type II collagen-immunized DBA1/J mice (0.1 mL/mouse), with the same stimulus repeated on day 21. Next, the CIA mouse model was selected, and inguinal lymph nodes were excised to obtain a single-cell suspension. Using CCK-8, control group, model group, and high-/medium-/low-dose diosgenin group were set based on drug toxicity. Next, the ratio of T-helper 17 cells (Th17) to CD3+ T cells was analyzed using flow cytometer. The levels of interleukin 17 (IL)-17 and IL-6 were determined by the enzyme-linked immunosorbent assay. The expression of RORγt was determined using the reverse-transcription quantitative real-time polymerase chain reaction and Western blot analysis. Results: An in vitro inhibitory rate of ≥ 70% was set as the cutoff value to select the high (25 μmol/L), medium (12.5 μmol/L), and low (6.25 μmol/L) doses of diosgenin. The Th17 cell ratio in CD3+ T cells, the levels of IL-17 and IL-6, and mRNA and protein expression of RORγt showed significantly increased tendency in the model group compared with the control group (P < 0.01 and/or P < 0.05). Diosgenin significantly decreased the Th17 cell ratio in CD3+ T cells, IL-17 and IL-6 levels, and RORγt expression when compared with the model group (P < 0.01 and/or P < 0.05). Conclusion: Diosgenin exhibited an antiarthritic effect in CIA mice by downregulating the differentiation of Th17 cells.