Liu Wei, Tan Zhenyu, Zhang Liming, Champion Christophe
School of Electrical Engineering, Shandong University, Jinan, 250061, Shandong, People's Republic of China.
School of Information Science and Electrical Engineering, Shandong Jiaotong University, Jinan, 250357, People's Republic of China.
Radiat Environ Biophys. 2018 May;57(2):179-187. doi: 10.1007/s00411-018-0730-0. Epub 2018 Jan 15.
This study presents the correlation between energy deposition and clustered DNA damage, based on a Monte Carlo simulation of the spectrum of direct DNA damage induced by low-energy electrons including the dissociative electron attachment. Clustered DNA damage is classified as simple and complex in terms of the combination of single-strand breaks (SSBs) or double-strand breaks (DSBs) and adjacent base damage (BD). The results show that the energy depositions associated with about 90% of total clustered DNA damage are below 150 eV. The simple clustered DNA damage, which is constituted of the combination of SSBs and adjacent BD, is dominant, accounting for 90% of all clustered DNA damage, and the spectra of the energy depositions correlating with them are similar for different primary energies. One type of simple clustered DNA damage is the combination of a SSB and 1-5 BD, which is denoted as SSB + BD. The average contribution of SSB + BD to total simple clustered DNA damage reaches up to about 84% for the considered primary energies. In all forms of SSB + BD, the SSB + BD including only one base damage is dominant (above 80%). In addition, for the considered primary energies, there is no obvious difference between the average energy depositions for a fixed complexity of SSB + BD determined by the number of base damage, but average energy depositions increase with the complexity of SSB + BD. In the complex clustered DNA damage constituted by the combination of DSBs and BD around them, a relatively simple type is a DSB combining adjacent BD, marked as DSB + BD, and it is of substantial contribution (on average up to about 82%). The spectrum of DSB + BD is given mainly by the DSB in combination with different numbers of base damage, from 1 to 5. For the considered primary energies, the DSB combined with only one base damage contributes about 83% of total DSB + BD, and the average energy deposition is about 106 eV. However, the energy deposition increases with the complexity of clustered DNA damage, and therefore, the clustered DNA damage with high complexity still needs to be considered in the study of radiation biological effects, in spite of their small contributions to all clustered DNA damage.
本研究基于对包括解离电子附着在内的低能电子诱导的直接DNA损伤谱的蒙特卡罗模拟，呈现了能量沉积与簇状DNA损伤之间的相关性。根据单链断裂（SSB）或双链断裂（DSB）与相邻碱基损伤（BD）的组合，将簇状DNA损伤分为简单型和复杂型。结果表明，约90%的总簇状DNA损伤相关的能量沉积低于150 eV。由SSB和相邻BD组合构成的简单簇状DNA损伤占主导地位，占所有簇状DNA损伤的90%，并且不同初级能量下与之相关的能量沉积谱相似。一种简单的簇状DNA损伤类型是一个SSB与1 - 5个BD的组合，记为SSB + BD。对于所考虑的初级能量，SSB + BD对总简单簇状DNA损伤的平均贡献高达约84%。在所有形式的SSB + BD中，仅包含一个碱基损伤的SSB + BD占主导（超过80%）。此外，对于所考虑的初级能量，由碱基损伤数量确定的固定复杂度的SSB + BD的平均能量沉积之间没有明显差异，但平均能量沉积随SSB + BD的复杂度增加而增加。在由DSB及其周围BD组合构成的复杂簇状DNA损伤中，一种相对简单的类型是DSB与相邻BD的组合，标记为DSB + BD，其贡献较大（平均高达约82%）。DSB + BD的谱主要由DSB与不同数量（从1到5）的碱基损伤组合给出。对于所考虑的初级能量，仅与一个碱基损伤组合的DSB占总DSB + BD的约83%，平均能量沉积约为106 eV。然而，能量沉积随簇状DNA损伤的复杂度增加而增加，因此，尽管高复杂度的簇状DNA损伤对所有簇状DNA损伤的贡献较小，但在辐射生物学效应研究中仍需考虑。
