목적: Acute lung injury (ALI) and its more severe form, the acute respiratory distress syndrome (ARDS), are syndromes of respiratory dysfunction that result from acute pulmonary edema, pulmonary contusions and inflammation. The role NADPH oxidase activation in acute lung injury (ALI) by pathogen is complex because reactive oxygen species contribute to both microbial killing and regulation of the acute pulmonary infiltrate. However the role of NADPH oxidase 2(NOX2) in host defense against <i>Pseudomonas aeruginosa</i> is not well-defined. 방법:Female C57BL/6, either wild type or gp91^phox-/-, aged 8 weeks, were exposed to <i>pseudomonas aeruginosa</i> for 24 hours. BAL was collected, and its cell count, BAL protein, LDH, CFU were measured. Cell counting were studied by Diff-Quik staining after cytospin. And Cytokine levels(TNF-a, IL-6) were measured by ELISA. 결과:Airway instillation of <i>Pseudomonas aeruginosa</i> strain 01 (PA01) to gp91^phox-/- demonstrated high level of BAL protein, and increased CFU in BAL fluid as compared with wild-type C57BL/6 mice, suggesting that gp91^phox-/- mice demonstrate impaired bacterial clearance. And decrease numbers of neutrophils in BAL fluid from gp91^phox-/- mice after infection with <i>Pseudomonas aeruginosa</i> was observed. 결론:Neutrophils are an important component of the inflammatory response that characterizes acute lung injury, but the potential contribution of neutrophils to host defense against <i>Pseudomonas aeruginosa</i> is unclear. So we focused on a correlation with NOX2 and neutrophils pyroptosis, programmed cell death associated with antimicrobial response, during <i>Pseudomonas aeruginosa</i>-induced acute lung injury.