缺血预适血减轻大鼠后肢缺血再灌注后肺损伤的实验研究

目的 探讨缺血预适应（IPC）对大鼠双侧后肢缺血再灌注（I／R）后肺损伤的影响及意义。方法 通过阻断肾下腹主动脉的方法建立双侧后肢I／R损伤模型。60只大鼠随机分为4组：假手术组（Ⅰ组，11：6）、缺血组（Ⅱ组，11=6）、I／R组（m组，n=24）、IPC＋I／R组（Ⅳ组，Ⅱ=24）。Ⅱ组在缺血4h末，Ⅲ组、Ⅳ组缺血4h并分别于再灌注后4、12、24和48h留取标本。观察肺组织形态学、湿／干重比、丙二醛（MDA）及髓过氧化物酶（MPO）的变化。原位杂交和逆转录多聚酶链反应（RT～PCR）方法检测肺组织中胞同粘附分子（I-CAM）-1的mRNA表达，Western蛋白印迹检测ICAIM-1。结果 Ⅲ组中，PMN计数、肺组织的湿／干重比、MDA、MPO显著增加（P〈0．01）、ICAM-1 mRNA反蛋白产物表达明显增强，与Ⅰ组或Ⅱ组比较差异显著（P〈0.01）。经IPC处理的Ⅳ组中上述各项指标明显减少，与Ⅲ组比较差异显著（P〈0．01）。结论 IPC减轻大鼠双侧后肢缺血再灌注后肺损伤，其作用机制可能是通过抑制ICAM-1介导的中性粒细胞在肺组织内的粘附、浸润而实现的。

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 (Group Ⅰ,n =6), ischemia group (Group Ⅱ, n =6), I/R group (Group Ⅲ, n =24), IPC+I/R group (GroupⅣ, 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 ⅠorⅡ (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 ICAM1 in the lung.