[Effects of Astragalus polysaccharide on imiquimod-induced psoriasiform dermatitis in mice and its mechanisms].

Objective: To investigate the effects and mechanisms of Astragalus polysaccharide on improving imiquimod-induced psoriasiform dermatitis in mice. Methods: Forty healthy female C57BL/6 mice were randomly divided into 5 groups, including blank control group, model group, astragalus polysaccharide high-dose group (200 mg/kg), medium-dose group (100 mg/kg) and low-dose group (50 mg/kg), with 8 mice in each group. The mice in model group and astragalus polysaccharide treatment group were treated with 5% imiquimod cream on the back to induce psoriasiform dermatitis. PASI score was monitored, and the secretion of inflammatory factors was determined by ELISA. The secretion of inflammatory factors was closely related to the infiltration of macrophages. The infiltration of macrophages in skin was detected by flow cytometry to further explore the effect of different concentrations of APS on psoriasis. Results: Compared with control group, the PASI score and the serum levels of TNF-α, IL-1β and IL-6 were increased significantly (P＜0.05), and the infiltration of macrophages in skin tissue was increased significantly in model group (P＜0.05). Compared with model group, the PASI score was decreased significantly (P＜0.05), and the serum levels of TNF-α, IL-1β and IL-6 were down-regulated significantly in astragalus polysaccharide high-dose and medium-dose groups (P＜0.05). The infiltrating macrophages in skin tissue were decreased significantly in Astragalus polysaccharide high-dose group (P＜0.05). Conclusion: Astragalus polysaccharide improve psoriasiform dermatitis in mice by inhibiting the infiltration of macrophages in skin tissue and decreasing the secretion of TNF-α, IL-1β and IL-6 in serum.