Ischemic Preconditioning Attenuated Lung Injury Following ischemia-reperfusion in Hind Limbs of Rats

【Objective】 To study the effect of ischemic preconditioning (IPC) on the lung injury following ischemia-reperfusion (I/R) in the hind limbs of rats. 【Methods】 Rat model of hind limbs I/R injury was established by cross-clamping below renal artery for 4 hours. Sixty rats were divided into 4 groups: sham operation group (GroupⅠ, n=6), ischemia group (Group Ⅱ, n=6), I/R group (Group Ⅲ, n=24), IPC+I/R group (Group Ⅳ, n=24). The last two groups received 4 hours of ischemia and then 4 hours, 12 hours, 24 hours or 48 hours of reperfusion. The tissue morphology, wet-to-dry weight (W/D) ratio, malondialdehyde (MDA) and myeloperoxidase (MPO) content in the lung were observed. mRNA expression of ICAM-1 in the lung was also determined by RT-PCR or in situ hybridization. The protein product was detected by western blot. 【Results】 In group Ⅲ, PMN count, W/D ratio, MDA and MPO content in lung increased significantly (P＜0.01). mRNA and protein expression of ICAM-1 in the lung increased significantly as compared with group Ⅰ or Ⅱ (P＜0.01). In group Ⅳ, the changes were meliorated significantly as compared with group Ⅲ (P＜0.01). 【Conclusion】 IPC can attenuate lung injury following I/R in the hind limbs of rats, which maybe accomplished by the inhibition of adhesion and infiltration of PMN after the expression of ICAM-1 in the lung.