Lineal energy-based evaluation of oxidative DNA damage induced by proton beams and X-rays
Lineal energy-based evaluation of oxidative DNA damage induced by proton beams and X-rays
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DOI：
10.3109/09553002.2012.715791
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发表时间：
2013-01-01
影响因子：
2.6
通讯作者：
Tsuboi, Koji
中科院分区：
文献类型：
--
作者：
Hong, Zhengshan;Kase, Yuki;Tsuboi, Koji
目的：为了确定质子束的氧化能力相比，X-射线的线性能量（y）的基础上，材料和方法：微剂量测定法被用来确定155 MeV质子的y值。用200 kV X射线（X）或155 MeV质子在其平台（P）和布拉格峰（B）附近照射鲑鱼睾丸脱氧核糖核酸（ST-DNA）溶液和人肿瘤细胞（MOLT-4）。8-高效液相色谱法测定羟基脱氧鸟苷（8-OHdG）的产量。通过琼脂糖凝胶电泳评估ST-DNA中的双链断裂（DSB），并通过磷酸化组蛋白H2 AX（gamma H2 AX）灶的免疫细胞化学分析评估细胞核中的DSB。结果：X作用下ST-DNA中8-OHdG的含量显著高于P和B，P作用下8-OHdG的含量显著高于B。使用P时ST-DNA中的DSB产量高于使用B或X时，尽管没有统计学显著性，但与使用B和X时几乎相等。虽然在MOLT-4细胞γ H2 AX焦点形成后，每种照射类型几乎是相同的，除了依达拉奉显着抑制焦点形成只有X.结论：我们的研究结果表明，自由基诱导的间接DNA损伤是显着低于质子束比X射线。
Purpose:To determine the oxidative capabilities of proton beams compared to X-rays based on lineal energy (y).Materials and methods: Microdosimetry was used to determine y-values of 155 MeV protons. Salmon testes deoxyribonucleic acid (ST-DNA) in solution and human tumor cells (MOLT-4) were irradiated with 200 kV X-rays (X) or 155 MeV protons at their plateau (P) and near their Bragg-peak (B). 8-Hydroxydeoxyguanosine (8-OHdG) production was determined by high performance liquid chromatography. Double-strand breaks (DSB) in ST-DNA were evaluated by agarose gel electrophoresis and DSB in cell nuclei were evaluated by immunocytochemical analysis of phosphorylated histone H2AX (gamma H2AX) foci. Edaravone was used as a radical scavenger.Results:8-OHdG yields in ST-DNA were significantly higher with X than with P or B, and they were significantly higher with P than with B. DSB yields in ST-DNA were higher with P than with B or X, although not statistically significant, and were nearly equal with B and X. Although gamma H2AX foci formation in MOLT-4 cells after each irradiation type was nearly identical, the addition of edaravone significantly inhibited foci formation only with X.Conclusions:Our results indicated that radical-induced indirect DNA damage was significantly lower with proton beams than with X-rays.