缺血预处理对大鼠肺缺血/再灌注损伤的保护作用

THE PROTECTIVE EFFECTS OF ISCHEMIC PRECONDITIONING ON REPERFUSION INJURY OF RAT LUNG

目的 :观察缺血预处理 (IPC)对大鼠肺缺血 /再灌注 (I/R)损伤的保护作用 ,并初步探讨其作用机制。方法 :建立离体大鼠肺灌流模型 ,36只wistar大鼠随机分为对照组、I/R组和IPC组 ,处理完毕后分别测定平均肺动脉压(MPAP)、肺组织湿 /干重比、支气管肺泡灌洗液中肺表面活性物质磷脂及表面张力改变 ,肺组织标本送电镜检查。结果 :①电镜下观察IPC组肺损伤明显减轻。②肺组织湿 /干重比值IPC组为 4.41± 0 .2 4,显著低于I/R组 ,但仍高于缺血前 (P <0 .0 1) ;③IPC组大鼠缺血 1h后MPAP为 ( 1.88± 0 .2 9)kPa ,明显低于I/R组 (P <0 .0 1) ;④IPC组支气管肺泡灌洗液中总磷脂为 ( 2 33 .42± 14.0 5 ) μg/kg ,大聚体为 ( 10 5 .39± 6 .17) μg/kg ,与I/R组相比显著增高 ,但低于对照组 (P <0 .0 1) ,三组之间小聚体含量没有显著差异 ;⑤IPC组表面张力为 ( 36 .88± 3.49)mN/m ,显著低于I/R组 ,与对照组相比则无显著性差异 (P >0 .0 5 )。结论 :缺血预处理对大鼠肺I/R损伤有保护作用 ,保护机制可能与促进肺表面活性物质 (PS)磷脂分泌、改善PS组成 ,从而提高PS功能有关。

Aim: To investigate the effects of ischemic preconditioning on reperfusion injury of rat lung. Methods: Rat isolated lungs(n=8 in each group) were stabilized and perfused by Krebs-Henseleit solution on a modified langendorff perfusion apparatus. 36 wistar rats were divided into three groups: ischemic preconditioning group, ischemia/reperfusion group and control group. Mean pulmonary artery pressure, wet/dry ratio, pulmonary surfactant phospholipid and alveolar surface tension in bronchoalveolar lavage fluid and electron microscope were detected. Results: The morphological changes of lung injury were alleviated in the preconditioning group under electron microscope. Wet/dry ratio, mean pulmonary artery pressure and SA/LA ratio were significantly lower in the preconditioning group after ischemic/reperfusion (P<0.01). Total phospholipid and large aggregate in the BALF were significantly increased in the preconditioning group (P<0.01). Small aggregate showed no change in three groups. Surfactant activity test showed that surface tension markedly decreased in IPC group(P<0.01). Conclusion: These results indicates that ischemic preconditioning may have a protective effect in ischemic/reperfusion injuried lung by ameliorating the content and function of surfactant phospholipid.