Khan Kainat, Tewari Shikha, Rastogi Madhup, Agarwal Gaurav Raj, Mishra Surendra Prasad, Husain Nuzhat
Department of Pathology, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, India. Email:
Asian Pac J Cancer Prev. 2018 May 26;19(5):1367-1373. doi: 10.22034/APJCP.2018.19.5.1367.
Background: Radiation causes oxidative lesions and strand breaks in DNA of exposed cells. Extended length PCR is a reliable method for assessing DNA damage. Longer DNA strands with DNA damage are difficult to amplify compared to smaller DNA strands by PCR. The present study was aimed to evaluate DNA damage caused by ionising radiation exposure in therapeutic and diagnostic medicine. Materials and Methods: The study group comprised 50 cases with low dose single exposure (LDS), low dose multiple exposure (LDM) and low dose angiography (LDA) which were compared with 25 high dose controls (HDC) and 25 controls with no exposure (NEC). Blood samples were collected within 1 hour of radiation exposure. DNA was isolated using a kit based protocol, 50 ng aliquots of DNA were used to amplify a long 13kbp DNA fragment of the β-actin gene by conventional PCR and band intensity was then quantified. Relative amplification was calculated and damage was expressed in terms of lesions per kilobase (kbp) by assuming a Poisson distribution. Result: Relative amplification was found to be 1.0, 0.87, 0.86, 0.72 and 0.69 with NEC, LDS, LDM, LDA and HDC groups, respectively. Cases undergoing angiography as well as high dose controls had high values, compared to NEC. The lesions/kbp calculated for LDS was 0.13, for LDM 0.15, for LDA 0.32 and for HDC 0.37 suggesting a linear increase in quantity with increasing radiation dose. Conclusion: DNA damage, even at low doses of radiation can be assessed by quantitative extra long PCR.
辐射会导致受照射细胞的DNA发生氧化损伤和链断裂。延伸长度PCR是评估DNA损伤的可靠方法。与较小的DNA链相比，存在DNA损伤的较长DNA链通过PCR更难扩增。本研究旨在评估治疗和诊断医学中电离辐射暴露所导致的DNA损伤。
研究组包括50例低剂量单次照射（LDS）、低剂量多次照射（LDM）和低剂量血管造影（LDA）病例，将其与25例高剂量对照（HDC）和25例未受照射对照（NEC）进行比较。在辐射暴露后1小时内采集血样。使用基于试剂盒的方案分离DNA，取50 ng DNA等分试样，通过常规PCR扩增β-肌动蛋白基因的13 kbp长DNA片段，然后对条带强度进行定量。计算相对扩增，并通过假设泊松分布以每千碱基（kbp）的损伤数来表示损伤情况。
NEC、LDS、LDM、LDA和HDC组的相对扩增分别为1.0、0.87、0.86、0.72和0.69。与NEC相比，接受血管造影的病例以及高剂量对照的值较高。LDS组计算出的每kbp损伤数为0.13，LDM组为0.15，LDA组为0.32，HDC组为0.37，表明随着辐射剂量增加，损伤数量呈线性增加。
即使在低剂量辐射下，DNA损伤也可通过定量超长PCR进行评估。
