Abdullaev Serazhutdin A, Minkabirova Gulchachak M, Bezlepkin Vladimir G, Gaziev Azhub I
Institute of Theoretical and Experimental Biophysics, Russian Academy of Science (RAS), Pushchino, Moscow Region, 142290, Russia,
Radiat Environ Biophys. 2015 Aug;54(3):297-304. doi: 10.1007/s00411-015-0599-0. Epub 2015 May 3.
Investigation of cell-free DNA (cf-DNA) in body fluids, as a potential biomarker for assessing the effect of ionizing radiation on the organism, is of considerable interest. We investigated changes in the contents of cell-free mitochondrial DNA (cf-mtDNA) and cell-free nuclear DNA (cf-nDNA) in the urine of X-ray-exposed rats. Assays of cf-mtDNA and cf-nDNA were performed by a real-time PCR in rat urine collected before and after irradiation of animals with doses of 3 and 5 Gy. We also determined the presence of mutations in urine cf-mtDNA, as recognized by Surveyor nuclease. A sharp increase in cf-mtDNA and cf-nDNA in the urine of irradiated rats was observed within 24 h after exposure, followed by a decrease to normal levels. In all cases, the contents of cf-mtDNA fragment copies (estimated by gene tRNA) were significantly higher than those of cf-nDNA estimated by gene GAPDH. A certain portion of mutant cf-mtDNA fragments was detected in the urine of exposed rats, whereas they were absent in the urine of the same animals before irradiation. These preliminary data also suggest that the increased levels of urine cf-mtDNA and cf-nDNA may be a potential biomarker for noninvasive assessment of how the organism responds to ionizing radiation influence.
研究体液中的游离DNA（cf-DNA）作为评估电离辐射对生物体影响的潜在生物标志物具有重要意义。我们研究了X射线照射大鼠尿液中游离线粒体DNA（cf-mtDNA）和游离核DNA（cf-nDNA）含量的变化。在动物接受3和5 Gy剂量照射前后收集的大鼠尿液中，通过实时PCR对cf-mtDNA和cf-nDNA进行检测。我们还通过Surveyor核酸酶确定尿液cf-mtDNA中是否存在突变。照射后24小时内，观察到照射大鼠尿液中cf-mtDNA和cf-nDNA急剧增加，随后降至正常水平。在所有情况下，cf-mtDNA片段拷贝数（通过基因tRNA估计）显著高于通过基因GAPDH估计的cf-nDNA拷贝数。在暴露大鼠的尿液中检测到一定比例的突变cf-mtDNA片段，而在同一动物照射前的尿液中未检测到。这些初步数据还表明，尿液cf-mtDNA和cf-nDNA水平的升高可能是无创评估生物体对电离辐射影响反应的潜在生物标志物。
