电离辐射诱导端粒延长作用的研究

目的观察人细胞系A549照射后端粒酶活性的变化及其对端粒长度的影响。方法采用端粒重复序列扩增法（TRAP）检测照射前、后不同时间点细胞端粒酶活性，端粒限制性片段平均长度分析法（耵谭）检测端粒长度。结果在1—5Gy剂量范围内A549端粒酶活性表达呈剂量和时间依赖性增强；照射后TRF延长，照射剂量越高，TRF延长出现越早，随着时间的延长，较低剂量组耵谭也明显延长，表明这种诱导作用与端粒酶表达增强有相近似的剂量效应和时间效应。结论端粒放射损伤可通过端粒序列的合成（延长端粒）进行修复；端粒酶可能在端粒放射损伤修复中起到重要作用。

Study on telomere lengthening induced by radiation

Objective To investigate changes of telomerase activities, and their affection on telomere length in irradiated human cell line A549. Methods Telomerase activity was assayed by TRAP, and telomere length was determined by mean length of terminal restriction fragment (TRF) analysis with probes complementary with telomere sequence at different time points before and after irradiation. Results Telomerase activity was up-regulated in a dosage-and timing-dependent manner after exposure to 1-5 Gy. TRF length analysis showed that the higher the dosage was, the earlier the TRF lengthening came forth, and TRF lengthening also appeared in lower dosag groups with the lapse of time after irradiation, suggesting that there were approximate dosage and timing effects between TRF lengthening and up-regulating of the activities of telomerase. Conclusion Radiation-damaged telomeres could be repaired by means of de novo composition of telomere sequences, in which telomerase might serve as a repairing factor.;