大鼠肢体缺血再灌注致肺损伤时肺组织中血红素氧合酶的表达

摘要

AIM:To observe the changes in heme oxygenase-1(HO-1) expression in the lung after ischmia-reperfusion of hind limbs in rats.METHODS:Hind limbs ischemia was made by clamping infrarenal aorta with a microvascular clip and lung injury was made by following reperfusion. Lung tissue was obtained from the animals subjected to sham operation, 4 h ischemia without reperfusion and 4 h, 8 h, 16 h, 24 h, 48 h reperfusion following 4 h ischemia. The levels of HO-1 mRNA and protein were measured at different times by Northern blot and Western blot. Immunohistochemistry technique was used to determine the cell types responsible for limb ischemic reperfusion induced HO-1 expression. RESULTS:After ischemia-reperfusion of limbs, HO-1 mRNA increased by 4 h, reached a peak at 16 h, and returned toward baseline at 24-48 h. This time course correlated with increased HO-1 protein. Immunohistochemical studies showed HO-1expressed in a variety of cell types, including the airway epithelium, alveolar macrophages and vascular smooth muscular cells. There were no positive signals in sham group and ischemia group both in mRNA levels and protein levels. CONCLUSION:The expression of HO-1 in the lung is not induced by limb ischemia or sham operation, but induced by limb reperfusion after ischemia in rats.%目的：观察大鼠肢体缺血再灌注致肺损伤时肺组织中HO-1表达的变化。方法：采用夹闭大鼠腹主动脉下段造成双下肢缺血和再灌注性肺损伤模型，分别采集假手术组，缺血4 h组及缺血4 h再灌注4、8、16、24、48 h组肺组织标本，以Northern印迹、Western印迹及免疫组化分析，观察HO-1表达的变化。结果：假手术组和单纯缺血组未见HO-1 mRNA表达；再灌注4 h可见其表达信号，且随着再灌注时间延长表达信号逐渐增强，到16 h时达到高峰，之后渐减弱，48 h时已消失。蛋白表达水平与mRNA表达一致。免疫组化研究显示，HO-1阳性信号主要出现在气道上皮细胞、血管平滑肌细胞和肺泡巨噬细胞，而假手术组和单纯缺血组均未见阳性信号。结论：假手术及肢体的单纯缺血未诱发肺组织HO-1的表达，而肢体缺血再灌注可诱发其表达，并具有时相变化。