中文摘要：

目的研究高浓度氧暴露对人肺泡Ⅱ型上皮细胞来源的肺腺癌A549细胞中硫氧还蛋白-2（thioredoxin-2，Trx-2）表达的影响，探讨Trx-2对高氧肺损伤线粒体的保护作用。方法体外传代培养A549细胞系，待其在37℃、5％CO2培养箱中生长至接近融合状态时，随机分为高氧组和空气组。高氧组持续暴露于常压高浓度氧中，氧浓度〉90％，CO2浓度为5％；空气组仍置于含5％CO2培养箱中。两组分别于高氧或空气暴露12、24、48h提取A549细胞总RNA，采取半定量逆转录聚合酶链反应（RT-PCR）测定Trx-2 mRNA的表达；采用Western blot检测A549细胞Trx-2蛋白的表达变化。结果①与空气组相比，A549细胞高氧暴露24h Trx-2 mRNA表达显著增强（P〈0．05）；48h后Trx-2 mRNA呈下降趋势，其表达较空气组减弱，但两者差异无显著性意义（P〉0．05）。②与空气组相比，A549细胞高氧暴露后12h Trx-2蛋白表达水平显著增强（P〈0．05），随后逐渐减弱，至48h显著减弱（P〈0．05）。结论高浓度氧暴露诱导A549细胞中Trx-2动态表达的变化，这种变化表明Trx-2对高氧肺损伤线粒体可能起重要的保护作用。

英文摘要：

Objective To investigate the effects of the expression of thioredoxin-2 in human adenocarcinoma of lung A549 cells from human alveolar epithelial cell Ⅱ exposed to high concentrations of oxygen and explore the protective effects of Trx-2 on mitochondria of A549 cells in hyperoxic lung injury. Methods A549 cells were passaged and cultured in vitro. When approaching to the condition of confluence in CO2 culture chamber （37℃ , 5% CO2 ）, the cells were randomly divided into air group and hyperoxia group. The cells in hyperoxia group were continuously exposed to oxygen （O2〉90 %, CO2=5 %）, while those in air group were still exposed to 5 % CO2. After exposure to oxygen or room air for 12, 24 and 48 h, total RNA of A549 cells was isolated and the expression of Trx-2 mRNA was detected by semiquantitative reverse transcription polymerase chain reaction （RT-PCR）. Western blot was used to detect the expression of Trx-2 protein in A549 cells. Results Compared with air group, Trx-2 mRNA expression was significantly increased （P〈0.05） in A549 cells exposed to hyperoxia for 24 h. At 48 h, there was no significant difference in the expression of Trx-2 mRNA between hyperoxia group and air group （P〉0.05）. Compared with air group, the Trx-2 protein expression was significantly increased （P〈0.05） in A549 cells after exposure to hyperoxia for 12 h, then gradually decreased, and significantly at 48 h （P〈0.05）. Conclusion Exposure to high concentrations oxygen can significantly change the expression of Trx-2 in A549 cells, which indicates that Trx-2 likely protects mitochondria of A549 cells in hyperoxic lung injury.