超高剂量率对生物分子辐射损伤的影响
Daniel Sforza1, Fred Bunz1, John Wong1
1Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD 21231.
Radiation research
|October 15, 2024
概括
与传统的剂量率相比,超高剂量速率 (UHDR) 辐射显著降低了DNA损伤,包括链断裂和集群病变. 这些发现凸显了剂量速率和基清除在辐射生物学中的重要性.
科学领域:
- 辐射生物学 辐射生物学
- 化学物理 化学物理
- 分子生物学分子生物学
背景情况:
- 剂量率会影响辐射诱导的生物分子损伤和毒性.
- 超高剂量率 (UHDR) 辐射模式显示出减少生物损伤的潜力.
- UHDR对DNA病变的质量和数量的影响尚不清楚.
研究的目的:
- 为了比较研究常规 (CONV) 和UHDR对DNA损伤形成的影响.
- 调查间接辐射对DNA链断裂和聚类损伤的影响.
- 评估基 (•OH) 清除和氧气水平对剂量依赖的DNA损伤的作用.
主要方法:
- 在不同的清理和环境条件下,在水溶液中对等离子体DNA (pUC19) 的辐射 (气化/无毒).
- 使用kVX射线系统利用常规 (0.1 Gy/s),高 (25 Gy/s) 和超高 (55, 125 Gy/s) 的剂量速率.
- 通过凝电泳和内核酶处理量化DNA损伤 (链断裂,集群损伤).
主要成果:
- 与CONV和HDR相比,UHDR (55和125 Gy/s) 在氧气的存在下诱导的DNA链断裂和集群损伤数量明显较低.
- 在UHDR照射后,DNA损伤的发生率下降了1.3-3.5的因素.
- 观察到的剂量比率效应取决于总剂量和OH清理能力,而不是轨道间重组或氧气去除.
结论:
- 高强度高强度辐射条件改变了生物分子损伤的质量和数量,特别是减少了DNA病变.
- 基清除能力和总剂量是调节剂量-速率对DNA影响的关键因素.
- 实验室等离子体DNA模型对于剖析辐射诱导生物分子损伤的剂量速率影响是有价值的.
相关概念视频
Biological Effects of Radiation
15.3K
All radioactive nuclides emit high-energy particles or electromagnetic waves. When this radiation encounters living cells, it can cause heating, break chemical bonds, or ionize molecules. The most serious biological damage results when these radioactive emissions fragment or ionize molecules. For example, α and β particles emitted from nuclear decay reactions possess much higher energies than ordinary chemical bond energies. When these particles strike and penetrate matter, they...
15.3K
Mutations
34.8K
Mutations are changes in the sequence of DNA. These changes can occur spontaneously or they can be induced by exposure to environmental factors. Mutations can be characterized in a number of different ways: whether and how they alter the amino acid sequence of the protein, whether they occur over a small or large area of DNA, and whether they occur in somatic cells or germline cells.
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
34.8K
Nucleotide Excision Repair
3.5K
DNA Distortion and Damage
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
3.5K
Overview of DNA Repair
30.9K
In order to be passed through generations, genomic DNA must be undamaged and error-free. However, every day, DNA in a cell undergoes several thousand to a million damaging events by natural causes and external factors. Ionizing radiation such as UV rays, free radicals produced during cellular respiration, and hydrolytic damage from metabolic reactions can alter the structure of DNA. Damages caused include single-base alteration, base dimerization, chain breaks, and cross-linkage.
Chemically...
Chemically...
30.9K


