Abstract: ObjectiveTo investigate the effects of disesel exhaust particles in air pollutants on airway hyperre sponsiveness and immunologic index in rats with asthma.MethodsSixty Wistar rats were rendomly dividedinto 6 groups.Grup A was control group.Group B was animal model group which was ovalbumin(OVA)sensitized challenged.Group C,D,E,F were challenged with 3% OVA and then exposed to diesel exhaust particles(DEP)for one to four weeks.The levels of IgE,interleukin 5(IL-5)and interferon(IFN-γ)of the lung tissue were detected by ELISA.ResultsThe airway hyperre sponsiveness of group B increased more than group A.Group B was significantly different from group E and F(F=156.186,P<0.01).Increase of airwag resistance was related with the time of DEP exposure(r=0.948,P<0.01).The concentration of IgE was significantly different between group A and B(F=2.490,P<0.01).The expression of IL-5 in lung tissue gradually increasedin group C.The expression of IL-5 in group B was significantly different from that of group C and E(F=4.263,P<0.01).The expression of IFN was not significantly different among the groups(F=1.193, P>0.05).ConclusionExposure to diesel exhaust particles might exacerbate airway hyperrespon siveness andinduce airway in flammation caused by IL-5 increase in the rats of asthma model.