Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9039, USA.
Int J Radiat Biol. 2010 Mar;86(3):194-204. doi: 10.3109/09553000903418603.
The DNA double-strand break (DSB) damage response induced by high energy charged particles on lung fibroblast cells embedded in a 3-dimensional (3-D) collagen tissue equivalents was investigated using antibodies to the DNA damage response proteins gamma-histone 2AX (gamma-H2AX) and phosphorylated DNA-PKcs (p-DNA-PKcs).
3-D tissue equivalents were irradiated in positions across the linear distribution of the Bragg curve profiles of 307.7 MeV/nucleon, 556.9 MeV/nucleon, or 967.0 MeV/nucleon (56)Fe ions at a dose of 0.30 Gy.
Patterns of discrete DNA damage streaks across nuclei or saturated nuclear damage were observed, with saturated nuclear damage being more predominant as samples were positioned closer to the physical Bragg peak. Quantification of the DNA damage signal intensities at each distance for each of the examined energies revealed a biological Bragg curve profile with a pattern of DNA damage intensity similar to the physical Bragg curve for the particular energy. Deconvolution microscopy of nuclei with streaked or saturated nuclear damage pattern revealed more details of the damage, with evidence of double-strand breaks radially distributed from the main particle track as well as multiple discrete tracks within saturated damage nuclei.
These 3-D culture systems can be used as a biological substrate to better understand the interaction of heavy charged particles of different energies with tissue and could serve as a basis to model space-radiation-induced cancer initiation and progression.
利用针对 DNA 损伤反应蛋白 γ-组蛋白 2AX（γ-H2AX）和磷酸化 DNA 依赖性蛋白激酶（p-DNA-PKcs）的抗体，研究嵌入三维（3-D）胶原组织等效物中的肺成纤维细胞中由高能带电粒子引起的 DNA 双链断裂（DSB）损伤反应。
3-D 组织等效物在横跨 307.7 MeV/nucleon、556.9 MeV/nucleon 或 967.0 MeV/nucleon（56）Fe 离子的布拉格曲线分布位置上进行照射，剂量为 0.30 Gy。
观察到核内离散的 DNA 损伤条纹或饱和核损伤的模式，随着样品更接近物理布拉格峰，饱和核损伤更为明显。对每个能量下每个检查点的 DNA 损伤信号强度进行定量，揭示了一个具有类似于特定能量物理布拉格曲线的 DNA 损伤强度的生物布拉格曲线分布。对具有条纹或饱和核损伤模式的核进行离焦显微镜分析，揭示了更多的损伤细节，有证据表明双链断裂从主粒子轨迹呈放射状分布，以及在饱和损伤核内有多条离散的轨迹。
这些 3-D 培养系统可用作更好地理解不同能量重带电粒子与组织相互作用的生物学基质，并且可以作为模型来研究太空辐射诱导的癌症起始和进展。
