miR-155-SIRT1在柴油机尾气暴露大鼠氧化应激和气道炎症中的作用

Role of miR-155-SIRTl in oxidative stress and airway inflammation in rats exposed to diesel engine exhaust

目的:探讨长期暴露柴油机尾气(DEE)对肺部炎症的影响以及潜在的机制。方法:30只Sprague-Dawley雄性大鼠随机分为DEE组和对照组,每组15只。DEE组暴露于含有3 mg/m 3柴油机排气微粒的DEE中12周,对照组暴露于净化空气中12周。使用酶联免疫吸附试验或高效液相色谱-串联质谱法检测尿液中2-羟基菲、9-羟基菲、8-羟基-2-脱氧鸟苷、丙二醛水平,血液和支气管肺泡灌洗液(BALF)中白细胞介素8(IL-8)、IL-6和肿瘤坏死因子α水平;肺组织病理切片观察肺炎症和重塑变化;荧光定量聚合酶链反应测定肺组织中miR-155水平;蛋白质印迹测定肺组织中沉默信息调节因子1(SIRT1)表达;通过双荧光素酶报告实验和免疫共沉淀实验验证miR-155与SIRT1的相互作用。 结果:DEE组大鼠尿中2-羟基菲、9-羟基菲、8-羟基-2-脱氧鸟苷、丙二醛水平,血清和BALF中IL-8、IL-6和肿瘤坏死因子α水平,BALF中白细胞总数、中性粒细胞、嗜酸粒细胞和淋巴细胞数均显著高于对照组( P值均<0.001),肺组织切片中气道炎症及重塑加重。与对照组比较,DEE组大鼠肺组织中miR-155水平升高( t=21.854, P<0.001),SIRT1表达下降( t=25.580, P<0.001)。miR-155模拟物下调SIRT1野生型细胞的荧光强度,而SIRT1在miR-155组中优先富集。 结论:DEE暴露加重大鼠气道炎症和氧化应激,可能与miR-155下调靶标SIRT1表达水平有关。

Objective To investigate the efects of long term diesel engine exhaust(DEE)exposure on lung inflammation and the underlying mechanisms.Methods Thirty Sprague Dawley male rats were randomly divided into DEE group and control group,fifeen rats in each group.The rats in DEE group were exposed to DEE with 3 mg/m2 of diesel exhaust particles for 12 weeks.The rats in control group were exposed to purified air for 12 weeks.The levels of 2-hydroxyphenanthrene(2-OHPh),9-OHPh,8-hydroxy-2-deoxyguanosine(8-OHdG),and malondialdehyde(MDA)in urine,interleukin-8(IL-8).IL-6,and tumor necrosis factor-a in blood and bronchoalveolar lavage fluid(BALF)were detected by enzyme linked immunosorbent assay or high performance liquid chromatography-tanderm mass spectrometry.Airway inflammation and remodeling changes in the lung were determined by histopathulogy.The levels uf miR 150 and silem infur latin legulatur 1(SIRT1)in lung tissue were detected by fluorescence quantitative polymerase chain reaction and W estern blot.The interaction between miR-155 and SIRTI was verified by luciferase reporter assay and RNA immunoprecipitation assay.Results The levels of 2 OHPh,9-OHPh,8-OHdG and MDA in urine,IL-8,IL-6.and tumor necrosis factor-a in serum and BALF,and total white blood cell,neutrophil,eosinophil,and lymphocyte number in BALF of DEE group were significantly higher than those of control group(all P<0.001).Airway inflammation and remolding were apparent in DEE group.Compared with the control group.the level of miR-155 was increased(t=21.854,P<0.001),SIRT1 expression decreased(t=25.580,P<0.001)in DEE group.miR-155 mimics downregulated the fluorescence intensity of SIRT1 wild-type cells,while SIRT1 was preferentially enriched in miR 155 group.Conclusions DEE exposure increases airway inflammation and oxidative stress in rats,which may be related to downregulating SIRT1 expression by miR-155.