ObjectiveTo investigate the effects of acute and chronic ozone exposure on inflammation,structure and function in murine lung. Methods32 C57/BL6 mice were randomly divided into a single (acute) ozone exposed group,a single air exposed group,a multiple (chronic) ozone exposed group (every three days over 6 weeks),and a multiple air exposed group with 8 mice in each group.The mice were exposed to 2.5 ppm of ozone or air for 3 hours per time and sacrificed 24 hours after the last time of ozone exposure.Lung volume,low attenuation area (LAA) percentage,lung function,cell counts and malondialdehyde (MDA) in bronchoalveolar lavage fluid (BALF),8-hydroxy-2'-deoxyguanosine (8-OHdG) in serum,inflammation scores and mean linear intercept (Lm) in lung section were assessed. ResultsCompared with the single air exposed group,single (acute) ozone exposure led to increases in inflammatory cells in BALF,inflammation scores in the lung tissue,MDA in BALF and 8-OHdG in serum,but had no effect on lung volume,LAA percentage,airflow or Lm.Compared with the single (acute) ozone exposed group,the single air exposed group and the multiple air exposed group,multiple (chronic) ozone exposure increased inflammatory cells in BALF,lung volume,LAA percentage,total lung capacity and lung compliance,mediated airflow obstruction,and also increased lung inflammation socres and Lm. ConclusionAcute ozone exposure induced airway/lung inflammation and oxidative stress,while chronic ozone exposure induced airway/lung inflammation,emphysema and airflow obstruction.