中文摘要：

[目的]探讨核因子E2相关因子2（Nrf-2）在纳米二氧化硅（nano—SiO2）致人支气管上皮细胞（16HBE）氧化应激损伤中的作用。[方法]分别以终浓度为1．0、2．5、5．0、10．0、25．0和50．0p,g／mLnano—SiO2处理人支气管上皮细胞24h，检测细胞活性。根据检测结果，确定本实验nano—SiO2（粒径15mm）的暴露浓度为2．5、5．0和10．0p,g／mL，分别设定为低、中、高浓度组。检测各暴露浓度组细胞内活性氧（ROS）、丙二醛（MDA）、总超氧化物歧化酶（T—SOD）和谷胱甘肽过氧化物酶（GSH-Px）等氧化应激相关指标。WesternBlotting检测细胞总蛋白和核蛋白中Nrf-2的表达水平，同时采用实时荧光定量聚合酶链反应检测Nrf-2基因mRNA表达水平。[结果]中、高浓度nano—Si02组16HBE胞内ROS水平明显增高（P〈0．01），同时T-SOD和GSH—Px含量降低（P〈0．05）；各浓度nano．Si02组16HBE胞内MDA含量均明显增高（P〈0．05）。与对照组相比，随着nano-SiO：暴露浓度的增高，细胞总Nrf-2蛋白和Mrf-2基因的表达水平呈先增高后降低的趋势，而核内Nrf-2蛋白表达水平均明显增高。[结论]15nm粒径的SiO：可诱导人支气管上皮细胞发生氧化应激性损伤，而Nrf-2的激活和核转位在调节细胞内氧化一抗氧化体系中起重要作用。

英文摘要：

[ Objective ] To examine the effect of nuclear factor E2-related factor 2 （Nrf-2） on silica nanoparticle （nano- SiO2）-induced oxidative damage to human bronchial epithelial cells. [ Methods ] Human bronchial epithelial cells （16HBE） were exposed to 1.0, 2.5, 5.0, 10.0, 25.0, and 50.0 μg/mL nano-SiO2 for 24h to determine cell viability. According to the results of cell viability assay, the cells in the following tests were then exposed to 2.5, 5.0, and 10.0 μg/mL nano-SiO2 （low, medium, and high dose groups, respectively）, and the tests included cellular reactive oxygen species （ROS）, malondialdehyde （MDA）, total superoxide dismutase （T-SOD）, and glutathione peroxidase （GSH-Px）. Western Blotting was used to estimate the expression levels of Nrf-2 in total and nuclear proteins, and real-time quantitative polymerase chain reaction was used to assess the mRNA expression level of Nrf-2. [ Results ] The cellular ROS level significantly increased （P 〈 0.01）, while T-SOD and GSH-Px levels decreased （P〈 0.05） in the medium and the high dose groups. The MDA contents significantly increased in the low, medium, and high dose groups （P 〈 0.05）. The total Nrf-2 protein and the Nrf-2 mRNA expression levels increased in the low dose group, while decreased in the medium and the high dose groups; and the nuclear Nrf-2 protein expression level significantly increased in the low, medium, and high dose groups. [ Conclusion ] In the current study settings, nano-SiO2 with 15 nm in size can induce oxidative damage in human bronchial epithelial ceils, and Nrf-2 activation and nuclear translocation play important roles in the regulation of intracellular oxidative-antioxidative system.