Investigation on Dose-Response Relationship of DNA Injury Induced byIonizing Radiation Using Single Cell Gel Electrophoresis

摘要

The effective medical management of a radiation accident required estimating appropriate biological dose inorder to provide diagnostic information to the treating physician. The classical cytogenetic biodosimetry included chromosomeaberration and mironuclei assay and so on, especially chromosome aberration, primarily introduced by Bender and Gooch,remained the “gold standard” for early-response accident biodosimetry and definitive dose assessments, but it wastime-consuming because of the lymphocyte culture about 48 to 72 hours. Investigators were eager to find a rapid, simple andsensitive method to serve as a biodosimetry. For this purpose, single cell gel electrophoresis(SCGE), also known as cometassay, was used to detect the DNA double-strand break of lymphocytes caused by 137Cs γ-ray irradiation in this study. Theradiation dose of 0, 0.5, 1, 2, 3, 4, and 5Gy were selected. The DNA fragments were moved to the anode, and then, a shape like“comet” was presented, which the tail toward the anode. The CASP system which donated by Wroclaw University of Polandwas used to analyse the pictures of comets. We selected four parameters included percentage of Tail DNA(TDNA%)、Taillength(TL)、Tail moment? and Olive tail moment(OTM), and all the data were statistical analyzed by One-way ANOVAand dose-response curve describing. Along with the increase of radiation dose, the degree of DNA damage was increased too,and a obvious dose-response relationship was found. The curves of TDNA% and TL were consistent with the Y＝a+bD mode,but that of TM and OTM were consistent with Y＝a+bD+cD2 mode.In this investigation, we established a modified method of neutral SCGE to detect the DNA double-strand break and drew theconclusion that it might be a biological endpoint for radiation biodosimetry.