Aim To investigate the relationship between oxidative stress and Fas/FasL system during lung ischemia reperfusion in rabbits.Methods Rabbit lung model of ischemia reperfusion injury was established in vivo.Forty rabbits were randomly divided into control group and ischemia reperfusion 1 h,3 h,and 5 h group,10 rabbits in each group.The activity of plasma superoxide dismutase,the content of plasma nitric oxide and the concentration of malondialdehyde,pneumocyte apoptosis index and express of Fas/FasL mRNA were measured respectively in different groups.Results Compared with control group,apoptosis index was significantly high(p<0.01),Fas/FasL mRNA heavily expressed in lung vascular endothelial cells,alveolar and bronchial epithelial cells in ischemia reperfusion groups(p<0.01).The activity of superoxide dismutase and the content of nitric oxide showed a time-dependent decrease in ischemia reperfusion groups(p<0.01),while the content of malondialdehyde was gradually increased with the time of reperfusion prolonging(p<0.01).Conclusion Oxidative stress was associated with activation of Fas/FasL during lung ischemia reperfusion.