中文摘要：

目的探讨高氧对胎鼠肺成纤维细胞（LFs）p53和增殖细胞核抗原（PCNA）表达的影响。方法原代培养胎鼠肺LFs,待生长至亚汇合状态时,随机分为：空气组和高氧组（95%O2/5%CO2）。于培养12 h和24 h时,采用噻唑蓝（MTT）实验测定细胞增殖状况,半定量RT-PCR方法检测p53 mRNA表达,Western blot技术检测p53和PCNA蛋白的表达。结果 （1）与空气组比较,高氧组12 h和24 h的LFs生长抑制率分别为8%和23%;（2）高氧组在12 h和24 h时p53 mRNA表达明显高于空气组（P〈0.01）;（3）高氧组在12 h和24 h时p53蛋白表达明显高于空气组（P〈0.01）,而PCNA蛋白表达水平在24 h明显低于空气组（P〈0.01）。结论高氧暴露抑制PCNA表达、促进p53表达,从而抑制LFs增殖和DNA复制,是导致肺发育异常的重要因素。

英文摘要：

Objective To study the effect of hyperoxia exposure on the expression of p53 and proliferating cell nuclear antigen（PCNA） in fetal rat lung fibroblasts（LFs）. Methods Primary rat embryonic LFs were cultured in vitro. LFs grew to subconfluence and then were randomly divided into air and hyperoxia exposure（95% O2, 5% CO2） groups. After LFs were cultured for 12 and 24 hours, the proliferation was analyzed by MTT. p53 mRNA level was detected by semi-quantitative reverse transcription polymerase chain reaction（RT-PCR）. p53 and PCNA protein levels were determined by Western blot. Results After 12 and 24 hours of culture the growth inhibition rate of LFs was 8% and 23% respectively in the hyperoxia exposure group. p53 mRNA and protein levels increased significantly（P〈0.01） in the hyperoxia exposure group after 12 and 24 hours of culture compared with the air exposure group. Hyperoxia exposure decreased PCNA expression after 24 hours of culture（P〈0.01）. Conclusions Hyperoxia exposure increases p53 level and decreases PCNA expression, resulting in inhibitions of LFs proliferation and DNA repair.