Sirota N P, Kuznetsova E A, Peleshko V N
Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino.
Radiats Biol Radioecol. 2007 May-Jun;47(3):297-301.
The purpose of this work was to study the chronic influence of the high-energy radiation field formed in the atmosphere at an altitude of 10 to 30 km on the level of DNA damage in leukocytes of peripheral blood in mice. The external radiation field (behind the concrete shield) of the U-70 accelerator (Serpukhov, Russia) was used for these studies. This radiation field simulates the components and spectral composition of the high-energy radiation field formed in the atmosphere at an altitude of 10 to 30 km. Two groups of SHK line mice were chronically irradiated with a total dose equivalent to 21.5 and 31.5 cGy. The state of the genome of nucleated blood cells was assessed by the Comet assay (alkaline version) 72 h after completion of chronic irradiation. The level of genome damage in individual peripheral blood leukocytes of irradiated animals was compared with the basal level of DNA lesions in peripheral blood leukocytes of unirradiated control mice. The damage was expressed in %TDNA (the amount of DNA found in the "comet tail" in percent of total DNA in the "comet"). It was found that in mice exposed to the radiation field of the accelerator, the mean value of DNA damage was: %TDNA = 3.88 +/- 0.35% for a dose of 21.5 cGy and % TDNA = 6.00 +/- 0.82% for a dose of 31.5 cGy. In mice irradiated at an X-ray therapeutic device with a dose of 150 cGy 24 h before the examination, %TDNA was 2.27 +/- 0.34% and this did not differ from %TDNA in unirradiated mice, 2.68 +/- 0.56%. We suggest that the increased level of DNA damage observed in mice irradiated with 31.5 cGy from the mixed radiation field at the Serpukhov accelerator points to the development of genetic instability in their leukocytes as a result of chronic exposure of animals to this particular radiation field.
这项工作的目的是研究在10至30千米高空大气层中形成的高能辐射场对小鼠外周血白细胞中DNA损伤水平的慢性影响。这些研究使用了U - 70加速器（俄罗斯谢尔普霍夫）的外部辐射场（在混凝土屏蔽后）。该辐射场模拟了在10至30千米高空大气层中形成的高能辐射场的成分和光谱组成。两组SHK系小鼠接受了总剂量相当于21.5和31.5 cGy的慢性照射。在慢性照射完成72小时后，通过彗星试验（碱性版本）评估有核血细胞的基因组状态。将受照射动物外周血单个白细胞中的基因组损伤水平与未受照射对照小鼠外周血白细胞中DNA损伤的基础水平进行比较。损伤以%TDNA表示（“彗星尾”中发现的DNA量占“彗星”中总DNA的百分比）。结果发现，暴露于加速器辐射场的小鼠中，DNA损伤的平均值为：21.5 cGy剂量下%TDNA = 3.88 +/- 0.35%，31.5 cGy剂量下%TDNA = 6.00 +/- 0.82%。在检查前24小时接受150 cGy X射线治疗设备照射的小鼠中，%TDNA为2.27 +/- 0.34%，这与未受照射小鼠的%TDNA（2.68 +/- 0.56%）没有差异。我们认为，在谢尔普霍夫加速器的混合辐射场中接受31.5 cGy照射的小鼠中观察到的DNA损伤水平升高表明，由于动物长期暴露于这种特定辐射场，其白细胞中出现了遗传不稳定性。
