Department of Dermatology, Copenhagen University Hospital - Bispebjerg, Copenhagen, Denmark;
Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark.
Anticancer Res. 2022 Oct;42(10):5069-5076. doi: 10.21873/anticanres.16015.
BACKGROUND/AIM: Solar ultraviolet radiation (UVR) is a carcinogen and irradiation of the skin results in DNA damage. Cyclobutane pyrimidine dimers (CPDs), including thymidine dimers, are among the most frequent forms of DNA damage. When CPDs are formed, the nucleotide excision repair system is activated and CPDs are excreted in the urine. Here, we developed a mass spectrometry-based method to quantify thymidine dimers in the urine and tested the method on a small group of volunteers after whole-body UVR exposure.
Years of research resulted in a method based on the "dilute-and-shoot" principle and ultra-performance liquid chromatography (UPLC) coupled to mass spectrometry. The whole body of each of eight healthy volunteers was exposed to 1.5-2.0 standard erythema doses (SEDs) of UVR for 3 consecutive days. Morning urine was collected on Day 1 (before irradiation) and on the following 7-9 days. Prior to analysis, sample preparation consisted of a simple dilution. A tandem quadrupole mass spectrometer coupled to UPLC was used for quantitative analysis in the multiple reaction monitoring mode.
After 3 consecutive days of 1.5-2 SEDs, the highest level of thymidine dimer excretion occurred on Day 6 (0.7 ng/ml urine). Compared with baseline, significantly more thymidine dimers were excreted every day until Day 8 (p<0.016). Our method quantifies thymidine dimers that are excreted as dimers (i.e., not degraded further) after nucleotide excision repair.
This is the first published mass spectrometry-based method for quantifying thymidine dimers in the urine after whole-body UVR exposure.
背景/目的：太阳紫外线辐射（UVR）是一种致癌物质，皮肤受到照射会导致 DNA 损伤。环丁烷嘧啶二聚体（CPD），包括胸腺嘧啶二聚体，是最常见的 DNA 损伤形式之一。当 CPD 形成时，核苷酸切除修复系统被激活，CPD 会在尿液中排出。在这里，我们开发了一种基于质谱的方法来定量尿液中的胸腺嘧啶二聚体，并在一小群志愿者全身 UVR 暴露后对该方法进行了测试。
多年的研究产生了一种基于“稀释和射击”原理的方法，并结合超高效液相色谱（UPLC）和质谱。八名健康志愿者的整个身体在连续三天内接受 1.5-2.0 个标准红斑剂量（SED）的 UVR 照射。第一天（照射前）和随后的 7-9 天收集早晨尿液。在分析之前，样品制备包括简单的稀释。串联四极杆质谱仪与 UPLC 结合，用于在多重反应监测模式下进行定量分析。
在连续 3 天接受 1.5-2 SED 后，第 6 天（尿液 0.7ng/ml）排泄的胸腺嘧啶二聚体水平最高。与基线相比，直到第 8 天（p<0.016），每天都有更多的胸腺嘧啶二聚体排泄。我们的方法定量了核苷酸切除修复后以二聚体形式（即进一步降解）排泄的胸腺嘧啶二聚体。
这是第一篇发表的基于质谱的方法，用于定量全身 UVR 暴露后尿液中的胸腺嘧啶二聚体。
