中文摘要：

[目的]探讨活性氧（ROS）在900 MHz微波辐射诱导γ射线致小鼠骨髓基质细胞DNA损伤的适应性反应中的作用。[方法]给予小鼠骨髓基质细胞120μW/cm-2,900 MHz微波照射,4 h/d,连续5 d,微波照射结束4 h后给予1.5 Gyγ射线照射,照射结束后立即采用碱性单细胞凝胶电泳试验和γ-H2AX焦点形成试验检测DNA损伤,观察微波辐射诱导的适应性反应;采用500 nmol/L褪黑素（ROS抑制剂）在微波照射前4 h处理细胞,流式细胞仪检测ROS水平的变化,观察适应性反应的变化情况。[结果]微波照射后细胞内ROS水平（2.10）较对照组（1.16）升高（P〈0.01）。与单独给予γ射线照射的彗星尾长、尾矩和γ-H2AX焦点形成数（分别为21.62μm、5.68、19.73）相比,预先给予微波照射可明显减轻随后γ射线照射造成的DNA损伤,彗星尾长、尾矩和γ-H2AX焦点形成数（分别为8.57μm、2.58、5.28）明显减少（P〈0.001）,诱导出适应性反应。褪黑素预处理细胞后,微波诱导产生的ROS下降为1.53（P〈0.01）,微波拮抗γ射线照射造成的DNA损伤程度也随之下降,彗星尾长、尾矩和γ-H2AX焦点形成数（分别为17.90μm、4.10、20.8）明显升高（P〈0.001）,适应性反应受到抑制。[结论]ROS可能在900 MHz微波辐射诱导细胞适应性反应中发挥作用。

英文摘要：

[ Objective ] To study the role of reactive oxygen species （ROS） in adaptive response induced by 900 MHz microwave radiation in mouse bone marrow stromal cells （BMSCs） exposed to 7 rays. [ Methods ] BMSCs were pre-exposed to 900MHz radiofrequency fields （RF） at 120μW/cm2 power intensity for 4h/d for 5 d and then subjected to an acute dose of 1.5 Gy γ-ray radiation. The level of DNA strand breaks was assessed by alkaline comet assay and γ-H2AX foci technique to confirm adaptive response induced by microwave radiation. The ceils were exposed to 500 nmol/L melatonin （an inhibitor for ROS） 4 h prior to the RF exposure to measure the level of ROS using flow cytometer and confirm adaptive response. [ Results ] The ceils exposed to RF showed a significantly increase of ROS （2.10） as compared to the control group （1.16） （P〈0.01）. The ceils preexposed to RF showed significant decreased DNA damage as well as reduced tail length, tail moment, and γ-H2AX foci （8.57 μm, 2.58, and 5.28, respectively） compared with those exposed to γ-radiation alone （21.62 μm, 5.68, and 19.73, respectively） （P 〈 0.001）, indicating that RF induced adaptive response. However, when the cells were subjected to melatonin prior to RF, the ROS level was decreased to 1.53 （P 〈 0.01）, and the DNA damage induced by subsequent γ-ray radiation decreased significantly as the tail length, tail moment, and γ-H2AX foci were increased （17.90 μm, 4.10, and 20.8, respectively） （P 〈 0.001）, indicating that adaptive response was inhibited. [ Conclusion ] ROS might play a role in the adaptive response induced by 900 MHz radiofrequency field at 120 μW/cm2 power density.