Abstract: Abstract Objective: Pneumoperitoneum performed to facilitate laparoscopy is associated with splanchnic perfusion, ischemia/reperfusion (I/R) injury, and oxidative stress. The current study evaluated the effect of laparoscopic preconditioning against laparoscopy-induced lung injury. Methods: 40 rabbits were randomly assigned to following groups. The control group(N) was subjected to a sham pneumoperitoneum. The short time group (S)was subjected to 1 hour of pneumoperitoneum. The long time group (L)was subjected to 3 hours of pneumoperitoneum.The laparoscopic preconditioning group(P) was subjected to 5 min of insufflation and 5 min of desufflation followed by 3 hours of pneumoperitoneum. After 20 min of desufflation subsequent to cessation of pneumoperitoneum, blood, lung, and bronchoalveolar lavage fluid(BALF) samples were obtained from every rabbit of the groups.white blood cell(WBC) count in BALF were detennined .The myleopemxidase (MPO) activity and wet to dry weight ratio(W/D)were also measured．Results: lung permeability index(LPI) and WBC count in BALF of group (L) are higher than the other three groups(p＜0.01),The lung tissue MPO activity of group (P) is much higher than group(S) and group(N) (p＜0.01),but it is lower than group (L).Conclusion: Lung injury induced by more than 3 hours of pneumoperitoneum is more effective than 1 hour of pneumoperitoneum. laparoscopic preconditioning is one of the ways which can inhibit the accumulation of PMNs in lung tissue，and thus attenuate the inflammatory response induced by more than 3 hours of pneumoperit -oneum rabbit lungs． Key words pneumoperitoneum ;ischemia-reperfusion injury; laparoscopic preconditioning ;lung;rabbit； polymorphonuclear leukocyte

Key words: pneumoperitoneum, laparoscopic preconditioning, polymorphonuclear leukocyte, lung, rabbit