Factors influencing heterogeneity of radiation-induced DNA-damage measured by the alkaline comet assay.
Factors influencing heterogeneity of radiation-induced DNA-damage measured by the alkaline comet assay.
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DOI：
10.1186/1748-717x-7-61
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发表时间：
2012-04-20
期刊：
影响因子：
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通讯作者：
Müller AC
中科院分区：
文献类型：
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作者：
Seidel C;Lautenschläger C;Dunst J;Müller AC
研究不同的DNA结构和辐射处理条件是否可以改变反应的异质性。此外，研究方差作为放射敏感性试验异质性的潜在参数。将每个健康捐赠者样本中的200个白细胞分为四组。I：完整的染色质结构; II：组蛋白耗尽的DNA的类核; III：组蛋白耗尽的DNA的类核，90 mM DMSO作为抗氧化剂。使用%Tail-DNA评价对4戈伊单次（I-III）和两次（IV）照射的反应和修复动力学。通过计算DNA损伤的方差（V）和均方差（Mvar）来确定DNA损伤的异方差性，用单因素方差分析（ANOVA）进行相互比较。初始DNA损伤（I，0分钟修复）的异质性增加而无组蛋白（II）。组蛋白的缺乏通过添加抗氧化剂来平衡（III）。修复降低了所有样品的异质性（有和没有照射）。然而，双照射加修复导致更高水平的异质性，与完整细胞中的单照射和修复不同。平均DNA损伤的增加与DNA损伤的类似升高的方差相关（r = +0.88）。DNA损伤的异质性可通过组蛋白水平、抗氧化剂浓度、修复和辐射剂量来调节，并与DNA损伤呈正相关。实验条件可能会优化，通过减少彗星试验数据的散射修复和抗氧化剂，可能允许更好的区分小的差异。通过方差测量的异质性量可能是表征放射敏感性的另一个有用参数。
To investigate whether different conditions of DNA structure and radiation treatment could modify heterogeneity of response. Additionally to study variance as a potential parameter of heterogeneity for radiosensitivity testing. Two-hundred leukocytes per sample of healthy donors were split into four groups. I: Intact chromatin structure; II: Nucleoids of histone-depleted DNA; III: Nucleoids of histone-depleted DNA with 90 mM DMSO as antioxidant. Response to single (I-III) and twice (IV) irradiation with 4 Gy and repair kinetics were evaluated using %Tail-DNA. Heterogeneity of DNA damage was determined by calculation of variance of DNA-damage (V) and mean variance (Mvar), mutual comparisons were done by one-way analysis of variance (ANOVA). Heterogeneity of initial DNA-damage (I, 0 min repair) increased without histones (II). Absence of histones was balanced by addition of antioxidants (III). Repair reduced heterogeneity of all samples (with and without irradiation). However double irradiation plus repair led to a higher level of heterogeneity distinguishable from single irradiation and repair in intact cells. Increase of mean DNA damage was associated with a similarly elevated variance of DNA damage (r = +0.88). Heterogeneity of DNA-damage can be modified by histone level, antioxidant concentration, repair and radiation dose and was positively correlated with DNA damage. Experimental conditions might be optimized by reducing scatter of comet assay data by repair and antioxidants, potentially allowing better discrimination of small differences. Amount of heterogeneity measured by variance might be an additional useful parameter to characterize radiosensitivity.