Effects of IL-4 mutant combined with soluble IL-5 receptor α on airway inflammation of asthmatic mice

Objective To observe the effects of IL-4 mutant combined with soluble IL-5 receptor on airway inflammation of asthmatic mice. Methods Fifty female BALB/c mice were randomly divided into 5 groups： the normal control group, the asthma group, the IL-4 MT treatment group, the sIL-5Rα treatment group,the combination of IL-4 MT and sIL-5Rα treatment group. Mice in asthma group and treatment group were sensitized and challenged by OVA. Mice in treatment groups were respectively injected intraperitoneally with IL-4 MT 100 μg,sIL-5Rα 100 μg and the combination of IL-4 MT 100 /,g and sIL-5Rα 100 μg 30 rain before challenged, while mice in normal group and asthma group received equal volume of saline. White blood cells（WBC） and eosinophils（EOS） in BALF were counted. HE staining was used to observe the pathological changes in lung tissue. Then the level of IL-4, IL-5 andEotaxin in BALF were measured by ELISA. Apoptosis of eosinophils in lung tissue was detected by TUNEL method. Results Compared with the normal group, the eosinophil ratio（ t =-50.48, P 〈 0. 001） and the levels of IL-4（ t =-12. 98, P〈 G0. 001）,IL-5（ t =-20. 51, P 〈0. 001）,Eotaxin（ t =-17.5（3, P 〈0. 001） in the asthma group were remarkably higher,and the apoptosis ratio （ t =5.35, P 〈0. 001） of eosinophils obviously lower. Compared with the asthma group,treatment groups can effectively reduce the eosinophils ratio （IL-4 MT treatment group t- 27.4, P 〈0. 001 ;sIL-5Rα treatment group t = 29.41, P 〈0. 001;the combination group t = 37.25, P 〈0. 001） and the levels of Eotaxin （IL-4 MT treatment group t =6.92, P 〈0. 001; sIL-5Rα treatment group t =4.96, P 〈0. 001; the combination group t = 9.95, P 〈0. 001） ,and enhance the apoptosis ratio of eosinophils （IL-4 MT treatment group t = -4.26, P 〈0. 001; sIL-5Rα treatment group t = -5.81, P 〈0. 001; the combination group t = -7.28, P 〈 0. 001）. Compared with single treatment,the combined treatment group were more effective. Conclusions IL-4 MT and sIL-5Rα could reduce IL-5, Eotaxin levels and promote apoptosis of eosinophils in asthmatic mice, which could be a useful therapeutic strategy to alleviate the airway inflammation of asthma. Key words: Asthma;  IL-4 Mutant;  Soluble IL-5 Receptor α ;  Eosinophils ;  Apoptosis