中文摘要：

目的：初步探讨2、4 Gy X射线照射后人肺腺癌A549细胞miR-505体内、外表达的变化及意义。方法：2、4 Gy X射线分别照射体外培养的A549细胞,以实时定量PCR（RT-q PCR）法检测A549细胞中miR-505表达水平。分别将0、2与4 Gy X射线照射后的A549细胞经尾静脉注射裸鼠制备裸鼠肺转移动物模型,检测裸鼠肺组织及血清中miR-505的表达水平。统计分析采用SPSS 19.0软件。结果：2 Gy X射线照射A549细胞后1、2、12、及24 h,miR-505表达均显著升高（升高倍数分别为：3.09、1.82、2.19及1.24倍,P〈0.01）;4 Gy X射线照射A549细胞后1、2、12 h,miR-505表达亦均显著升高（升高倍数分别为：2.99、2.06、1.86倍,P〈0.01）。0、2、4 Gy X线照射组裸鼠肺组织中均可检测到miR-505表达显著升高（升高倍数分别为：9.28、16.55及6.84倍,P〈0.05）;miR-505在血清中表达水平0 Gy和2 Gy组分别为5.33和3.78,与对照组相比显著升高（P〈0.05）。结论：2、4 Gy X射线照射可增加A549细胞miR-505的体内、外表达水平,可能与增强A549细胞体内、外侵袭转移能力相关。

英文摘要：

Objective： To investigate the expression of miR-505 in 2 and 4 Gy X-ray irradiated A549 cells in vitro and in vivo. Methods： Real-time quantitative PCR（ RT-q PCR） assay was employed to detect the expression miR-505 in 2 and 4 Gy X-ray irradiated A549 cells in vitro and in vivo. Statistical analysis was performed using SPSS 19. 0 software. Results： Compared with the control group,the expression of miR-505 were up-regulated significantly in X-ray irradiated A549 cells 1,2,12 and 24 hours post irraditaion,respectively（ fold change was 3. 09,1. 82,2. 19 and 1. 24 with 2 Gy irradiation,P 〈0. 01） and 1,2 and 12 hours post irraditaion respectively（ fold change was 2. 99,2. 06 and 1. 86 with 4 Gy irradiation,P〈 0. 01）. Furthermore,the expression of miR-505 was up-regulated in the lung and serum of nude mice with injection of 0,2 and 4 Gy X-ray irradiated A549 cells,compared with control group（ fold change was 9. 28,16. 55 and 6. 84 with 2 Gy irradiation,respectively,P 〈0. 05）. The expression of miR-505 were up-regulated in the serum of nude mice with injection of 0 and 2 Gy X-ray irradiated A5 4 9 cells,compared with control group（ fold change was 5. 33 and 3. 78 with 2 Gy irradiation,respectively,P〈 0. 05）. Conclusion： 2 and 4 Gy X-ray could up-regulated the expression of miR-505 of A549 cells,which might be correlated with the enhanced metastasis of A549 cells induced by X-ray in vitro and in vivo.