Zileuton对局灶性脑缺血/再灌注致急性肺损伤的保护作用

Protective effects of zileuton on the acute lung injury induced by focal cerebral ischemia-reperfusion in rats

目的探讨选择性5-脂氧合酶(5-LO)抑制剂zileu-ton对局灶性脑缺血/再灌注损伤(CIRI)引发急性肺损伤(ALI)的保护作用及其机制。方法线栓法制作大鼠大脑中动脉闭塞/再灌注(MCAO/R)模型,缺血2h,再灌注24h。于缺血前2h,再灌注0、5、10h,分别4次灌胃给予zileuton 10、50mg·kg-1。HE染色观察肺组织形态学改变;湿干重比(W/D)检测肺组织含水量;RT-PCR法检测肺组织白三烯受体1 mRNA(CysLTR1 mRNA);酶联免疫吸附法(ELISA)检测血清白三烯B4(LTB4)浓度;免疫组化法检测肺组织肿瘤坏死因子-α(TNF-α)蛋白;生化法检测肺组织髓过氧化物酶(MPO)、总抗氧化能力(T-AOC)和Na+,K+-ATPase活性。结果Zileuton10、50mg·kg-1均可改善肺组织病理变化,减少肺组织W/D比值(P<0.01),并下调肺组织CysL-TR1mRNA和TNF-α蛋白表达(P<0.05,P<0.01),降低血清LTB4浓度(P<0.01),缓解肺组织MPO升高和Na+,K+-ATPase活性下降(P<0.05,P<0.01),提高肺组织T-AOC(P<0.05,P<0.01)。结论Zileuton可有效抑制CIRI所致的ALI,其机制与抑制5-LO通路活性,减轻肺组织炎症反应、氧化损伤和离子转运障碍有关。

Aim To investigate the protective effects and mechanisms of a 5-lipoxygenase （5-LO） inhibitor zileuton on the acute lung injury （ALI） induced by focal cerebral ischemia-reperfusion injury （CIRI） in rats.Methods The right middle cerebral artery in rats were occluded by inserting a thread through internal carotid artery for 2 h,and then reperfused for 24 h.Zileuton（10,50 mg·kg-1） was orally administered 2h before ischemia and 0,5,10 h after reperfusion.Morphological changes of the lung tissue were observed by hematoxylin-eosin （HE）staining technique. Lung wet/dry weight ratios were detected to observe the water content of the lung. The mRNA of cysteinyl leukotrienes recepor1 （CysLTR1） was detected by RT-PCR. The content of Leukotriene B4 （LTB4） in serum was measured by enzyme linked immunosorbent assay （ELISA） technique. The expression of TNF-α protein was measured by immunohistochemical technique. The activities of MPO, T-AOC, and Na＋,K＋-ATPase from the lung tissue were measured by biochemical method.Results With the use of zileuton 10, 50 mg·kg-1,the pathological changes of the lung were alleviated. and the wet/dry weight in the lung tissue was reduced（P0.01）. Simultaneously, the content of LTB4 in serum was dramatically reduced（P0.01）, the expressions of CysLTR1 mRNA and TNF-α protein in the lung tissue significantly inhibited（P0.05,P0.01）, the activity of MPO reduced and the activities of T-AOC and Na＋,K＋-ATPase increased in the lung tissue（P0.05,P0.01）.Conclusion A 5-LO inhibitor zileuton can play a protective role on the ALI after CIRI. The protective mechanism maybe related with zileuton inhibits the activity of 5-LO pathways,thus alleviating the inflammation reaction and lipid peroxidation and protecting the activity of Na＋,K＋-ATPase in the lung tissue.