Abstract： Objective To explore apoptosis of lung tissues in dogs with acute lung injury coupled with thoracic seawater immersion and changes in gene expression following open chest injury.Methods The dogs with acute lung injury induced by open chest injury coupled with thoracic seawater immersion were used as the experimental group,and the dogs with just simple open chest injury were used as control animals.Tunel method was used to detect changes in the apoptosis of lung tissues of both animal groups,and immunochemistry was applied to detect changes in the expressions of Fas/FasL and nuclear factor-k-gene binding (NF-κB).Results Apoptosis of alveolar epithelial cells and pulmonary vascular endothelial cells in the animals of the experimental group was significantly increased,when compared with that of the control group ( P ＜ 0.05 ).The expressions of Fas/FasL and NF-κB in the experimental dogs were also increased considerably,when compared with those of the control group (P ＜ 0.05).Conclusions Apoptosis of alveolar epithelial cells and pulmonary endothelial cells was involved in the development of acute lung injury induced by open chest injury coupled with thoracic seawater immersion,and Fas/FasL system might be one of the important factors contributing to the apoptosis of lung tissues.