Objective: Mice Type2 allergic contact dermatitis induced by fluoresciniso thiocyate (FITC) was utilized in this study to explore the effect of astragaioside Ⅳ(AS-Ⅳ) on allergic inflammatory. Method: The BALB/c mice were topically sensitized on the shaved abdomens with 1.5% FITC solution at day 1 and day 2 and elicited on the right ear with 0.5% FITC at day 6.Mice in the dexamethasone group were intraperitoneal injection with dexamethasone(0.67 mg·kg-1) and the AS-Ⅳ group were intragastrically administered with astragaioside Ⅳ(6.25

12.5

25

50 mg·kg-1) from day 1 to day 5 (induction phase). Auricle swelling was measured 24 h after the elicitation. Pathohistological examination was carried out by HE staining.Interleukin-4( IL-4)

IL-13 and IL-9 levels of ear tissue homogenates were detected by ELISA. Result: Compared with the normal group

ear swelling in model group was stimulated by FITC treatment significantly and ear tissue local edema

angiectasis and lymphocytic infiltration were observed simultaneously. Meanwhile

IL-4

IL-13 and IL-9 levels increased remarkably in FITC treated mice. Wherein

AS-Ⅳ 25 mg·kg-1 and 50 mg·kg-1 evidently inhibited the auricle inflammation of the FITC treated mice. Pathohistological results indicated that AS-Ⅳ alleviated local edema and angiectasis of mice models and reduced lymphocytic infiltration significantly. Furthermore

IL-4

IL-13 and IL-9 levels in ear tissue homogenates were markedly decreased by AS-Ⅳ treatment. Conclusion: Administration with AS-Ⅳ in induction phase could inhibit Th2 cell-mediated allergic contact dermatitis in mice significantly and this effect was related with regulation on type 2 cytokines.