Ogg1P and Ogg1Dmice were RWPE -challenged, and exfoliated AECs were subjected to Comet assays. (A) Kinetics of changes in SSB levels in the airway epithelium from Ogg1Pand O gg1D mice after RWPE challenge. For each time points and treatments, >200 comet moments were evaluated. (B) Representative comet moments under neutral (left images) and alkaline (right images) electrophoretic conditions, representing DNA double-strand breaks and single-strand breaks, respectively, 16 h after RWPE challenge. CA, comet assay; Ogg1P, mice proficient in Ogg1 expression in the airway epithelium; O gg1D, mice deficient in Ogg1 expression in the airway epithelium; RWPE, ragweed pollen grain extract; SSBs, single strand breaks;. *P< 0.05, ** P< 0.01, *** P< 0.001.