The sensitivity of the alkaline comet assay in detecting DNA lesions induced by X rays, gamma rays and alpha particles
The sensitivity of the alkaline comet assay in detecting DNA lesions induced by X rays, gamma rays and alpha particles
复制标题
DOI：
10.1093/rpd/ncl424
复制
发表时间：
2006-12-01
影响因子：
1
通讯作者：
Gomolka, M.
中科院分区：
文献类型：
--
作者：
Roessler, U.;Hornhardt, S.;Gomolka, M.
设计并进行实验以研究具有不同能量的光子辐射（29 kV、220 kV X射线; Co-60、Cs-137-γ射线）和来自Am-241源的α辐射的不同细胞能量沉积模式在人细胞中的DNA损伤诱导能力是否不同。为此，应用碱性彗星试验（单细胞凝胶电泳）测量与接受剂量相关的DNA损伤量。人外周淋巴细胞的参数“尾中DNA %"和”尾矩“的彗星试验数据表明，无论是在0-3戈伊的总平均剂量范围内还是在低剂量范围内，29 kV X射线相对于参考辐射、220 kV X射线和伽马射线产生的初始辐射损伤均无任何差异。相比之下，当分析“尾长”数据时，在约1.5戈伊的X射线下出现拟合剂量响应曲线的饱和，但在高达3戈伊的伽马射线下不明显。HSC 45-M2细胞的α暴露的初步数据显示，仅在高剂量（> 2戈伊Am-241）下DNA损伤显著增加，但2戈伊下的损伤超过2戈伊下由Cs-137-γ射线诱导的损伤2.5倍。相比之下，涉及不同细胞系统和DNA损伤指标如染色体畸变的其他实验已经检测到在低得多的剂量下DNA损伤的显著增加，即Am-241在0.02戈伊下，并显示出更高的生物学有效性。这些结果表明，生物效应的差异是通过复杂DNA损伤的下游加工产生的。
Experiments were designed and performed in order to investigate whether or not the different cellular energy deposition patterns of photon radiation with different energies (29 kV, 220 kV X rays; Co-60, Cs-137-gamma-rays) and alpha-radiation from an Am-241 source differ in DNA damage induction capacity in human cells. For this purpose, the alkaline comet assay (single cell gel electrophoresis) was applied to measure the amount of DNA damage in relation to the dose received. The comet assay data for the parameters '% DNA in the tail' and 'tail moment' for human peripheral lymphocytes did not indicate any difference in the initial radiation damage produced by 29 kV X rays relative to the reference radiations, 220 kV X rays and the gamma rays, whether for the total mean dose range of 0-3 Gy nor in the low-dose range. In contrast, when the 'tail length' data were analysed saturation of the fitted dose response curve appeared for X rays at about 1.5 Gy but was not apparent for gamma rays up to 3 Gy. Preliminary data for alpha exposures of HSC45-M2 cells showed a significant increase in DNA damage only at high doses (> 2 Gy Am-241), but the damage at 2 Gy exceeded the damage induced at 2 Gy by Cs-137-gamma-rays by a factor of 2.5. In contrast, other experiments involving different cell systems and DNA damage indicators such as chromosomal aberrations have detected a significant increase in DNA damage at much lower doses, that is at 0.02 Gy for Am-241 and depicte a higher biological effectiveness. These results indicate that differences in biological effects arise through downstream processing of complex DNA damage.