ABSTRACT
Objective:To optimize the challenge scheme for establishing a stable mouse model of Artemisia annua pollen-induced allergic rhinitis. Methods:BALB/c mice were subcutaneously injected with 0.1 ml allergen extract containing 20 μg/ml Art a1 from Artemisia pollen on 1 d, 4 d and 7 d. One week after the sensitization, these mice were divided into three groups and intranasally challenged with Artemisia annua pollen allergen extract containing 500 μg/ml Art a1 for 7 (7 d group), 10 (10 d group) and 14 (14 d group) consecutive days, respectively. The first challenge was followed by another 7 days of challenge every four weeks. Blank control group was set up through sensitizing and challenging BALB/c mice with normal saline. Behavioral changes and nasal pathological changes were observed. The changes in humoral and cellular responses were also detected. After the first challenge cycle was decided, the challenge frequency was further optimized. Results:After the first challenge, the allergic symptoms of mice in 10 d group were significantly severe than those in 7 d and 14 d groups, and the levels of serum specific IgE antibody in 10 d and 14 d groups were significantly higher than that in 7 d group. After the second challenge, the mice in the three model groups still had obvious allergic symptoms as compared with the blank control group. There were obvious pathological changes in the nose, including epithelial cell proliferation, turbinate enlargement and inflammatory cell increase. Moreover, the level of serum specific IgE antibody increased significantly and the proliferation of antigen-specific IL-4 and IL-6 lymphocytes was significantly up-regulated, especially in 10 d and 14 d groups. The frequency of challenge had a great impact on the stability of the allergic model. The allergic symptoms of sensitized mice challenged every two weeks were significantly severe than those of mice challenged every four weeks and the level of serum antigen-specific antibody was also higher.Conclusions:This study optimized the first challenge cycle and challenge frequency for establishing a mouse model of Artemisia annua pollen-induced allergic rhinitis, which provided reference for the establishment of drug efficacy evaluation system for desensitization therapy.