肢体缺血预处理对兔肺缺血再灌注损伤的影响

Effects of preconditioning with leg ischemia on lung ischemia-reperfusion injury in rabbits

目的探讨肢体缺血预处理对兔肺缺血再灌注损伤的影响。方法健康日本大耳白兔18只，体重2．0～2．5kg，雌雄不拘，随机分为3组（n=6）：假手术组（S组）开胸后左侧肺门穿线但不结扎，旷置观察340min；缺血再灌注组（IR组）开胸旷置100min，阻断左侧肺门，左肺不张后60min再灌注180min；肢体缺血预处理组（L组）捆绑双后肢10min，松开10min，反复3次后恢复灌注，60min后阻断左侧肺门60min，再灌注180min。于缺血前、再灌注15、30、60、120、180min时采集左颈内动脉血样行血气分析，计算呼吸指数（RI）；于再灌注180min时处死动物，取左肺上叶组织，测定超氧化物歧化酶（SOD）、髓过氧化物酶（MPO）活性及丙二醛（MDA）含量，计算肺湿于重比（W／D）；取左肺下叶行支气管肺泡灌洗，计算肺通透性指数；取左肺中叶组织，观察肺组织病理学，进行弥漫性肺泡损伤（DAD）评分。结果与S组比较，IR组RI、MDA含量、MPO活性、肺W／D、肺通透性指数和DAD评分升高，SOD活性降低（P〈0．05或0．01）；与IR组比较，L组RI、MDA含量、MPO活性、肺W／D、肺通透性指数和DAD评分降低，SOD活性升高（P〈0．05或0．01）；L组和S组间上述指标比较差异无统计学意义（P〉0．05）。L组和S组肺组织病理损伤程度较IR组减轻。结论肢体缺血预处理可减轻兔肺缺血再灌注损伤。

Objective To evaluate the effects of leg isehemic preconditioning on lung ischemiareperfusion （I/R） injury in rabbits. Methods Eighteen healthy Japanese long-ear white rabbits of both sexes weighing 2.0- 2.5 kg were randomly divided into 3 groups （ n = 6 each） ： group Ⅰ sham operation （group S） ; group Ⅱ I/R and group Ⅲ leg ischemic preconditioning （group L）. The animals were anesthetized with iv barbital sodium （1 ml/kg） 25 g/L. Tracheal intubation was performed and the animals were mechanically ventilated. The left hilum of lung was threaded but no occlusion was performed and then the animals were observed for 340 min in group S. Left lung I/R was produced by left hilum of lung occlusion for 60 min followed by 180 min reperfusion in group I/R. Leg ischemia was induced by placing tourniquet on both legs. The animals underwent 3 episodes of 10 mix leg ischemia at 10 min intervals, and 60 mix later left hilum of lung was occluded for 60 mix followed by 180 min reperfusion in group L. Blood samples from left internal carotid ＇artery were taken for blood gas analysis before ischemia and at 15, 30, 60, 120 and 180 mix of reperfnsion. Respiratory index （RI） was calculated. The animals were killed al 180 mix of reperfusion and the lungs were removed for determination of SOD and MPO activities, MDA content, calculation of W/D lung weight ratio, and lung permeability index （LPI） in broncho-alveolar lavage fluid （BALF）, and histological examination with light microscrope, and diffuse alveolar damage （DAD） was scored. Results Compared with group S, RI, MDA content, MPO activity, W/D lung weight ratio, LPI in BALF and DAD scores were significantly increased while SOD activity decreased in group I/R （ P 〈 0.05 or 0.01） . RI, MDA content,MPO activity, W/D lung weight ratio, LPI in BALF and DAD scores were significantly lower while SOD activity higher in group L than in group I/R （P 〈 0.05 or 0.01） . There were no significant differences in the indices mentioned above between group L and S. The histological damages were significantly milder in group S and L than in group I/R. Conclusion Leg ischemie preconditioning can attenuate the lung I/R injury in rabbits.