Objective:To investigate the effects of N-acetylcysteine(NAC)on the number of Clara cells and secretion of Clara cell16000(CC16)protein in murine asthmatic model.Methods:The murine asthmatic model was established by sensitiz-ing and challenging BALB/c mice with ovalbumin(OVA).Thirty mice were divided into control,asthmatic and NAC groups (n=10). The number of Clara cells and synthesis of CC16were determined by immunohistochemistry.The CC16level in bronchoalveolar lavage fluid(BALF)was determined by Western blot.Results:The proportions of Clara cells in terminal and respiratory bronchioles were(58.05?3.75)%and(63.70?1.79)%in the asthmatic group,(74.54?5.81)%and (78.46?1.68)% in the control(P