Abstract: AIM:To explore the protective effects and mechanism of astragalus injection on asthmatic rats.METHODS:OVA was injected intraperitoneally and inhaled to produce the asthmatic rat models.Forty rats were randomly divided into five groups :control group, asthma group and astragalus groups of high, medium and low dose.The concentration of IL-5 in BALF and the expression of IL-5 mRNA, phospho-p38 MAPK in lung tissue were respectively measured by ELISA, in situ hybridization staining and Western blot.The number of inflammatory cell in BALF was calculated and histopathology changes were observed. RESULTS:The number of inflammatory cell and the concentration of IL-5 in BALF and the expression of IL-5 mRNA, phospho-p38 MAPK in lung tissue were higher in asthmatic rat group than those in normal control(P<0.01);and those in astragalus rat group were lower than in asthmatic rat group(P<0.01).The histopathology damage was alleviated in astragalus rat group.The efficacies in the astragalus groups of high, medium and low dose were similar, showing no insignificant difference among them.The expression of phospho-p38 MAPK has positive correlation with the number of eosinophil and the concentration of IL-5, the 中国临床药理学与治疗学 2008 Aug;13(8)· 903· expression of IL-5 mRNA(r=0.62, 0.69, 0.74, P<0.01).CONCLUSION:p38 MAPK may play a role in pathological process of asthma.Astragalus could effectively treat asthma by inhibiting the expression of phospho-p38 MAPK and IL-5, and decreasing the number of inflammatory cells

Key words: asthma, mitogen-activated protein kinase, astragalus, airway inflammation, cytokine