Foray N, Fertil B, Alsbeih M G, Badie C, Chavaudra N, Iliakis G, Malaise E P
Laboratoire de Radiobiologie, Institut Gustave-Roussy, Villejuif, France.
Int J Radiat Biol. 1996 Feb;69(2):241-9. doi: 10.1080/095530096146084.
We measured DNA double-strand breaks (dsbs) immediately after exposure of a non-transformed human fibroblast cell line (HF19) to gamma-rays (0-40 Gy) at four dose-rates (10, 1, 0.1, and 0.01 Gy/min) at 37 degree C using clamped homogeneous electric field (CHEF) gel electrophoresis. The shape of the dose-response curves, which could be approximated by a straight line over the range 0-20 Gy for irradiation at 4 degree C, became curvilinear when irradiation was carried out at 37 degree C at 10, 1, 0.1, and 0.01 Gy/min and reached a plateau at 10 Gy after irradiation at 0.01 Gy/min. We present a mathematical analysis that predicts the results of irradiation at 37 degree C from dsb induction and repair data obtained at 4 degree C, followed by incubation for repair at 37 degree C. The model assumes that the rate of dsb rejoining changes continuously with repair time and that it is independent of dose and dose-rate in the range 10-40 Gy. The model also assumes a linear induction of dsb with dose at 4 degree C and dsb induction is independent of dose-rate and of temperature during irradiation. Independent measurements of dsb induction at 4 degree C and of repair rate accurately predict the dsb levels after irradiation at 37 degree C, during which both phenomena occur simultaneously.
我们使用钳位均匀电场（CHEF）凝胶电泳，在37℃下，以四种剂量率（10、1、0.1和0.01 Gy/分钟）将非转化的人成纤维细胞系（HF19）暴露于γ射线（0 - 40 Gy）后，立即测量DNA双链断裂（dsbs）。在4℃照射时，剂量响应曲线的形状在0 - 20 Gy范围内可近似为一条直线，而当在37℃以10、1、0.1和0.01 Gy/分钟的剂量率进行照射时，曲线变为曲线形，并且在以0.01 Gy/分钟照射后，在10 Gy时达到平台期。我们提出了一种数学分析方法，该方法根据在4℃获得的dsb诱导和修复数据，预测37℃下的照射结果，然后在37℃下进行修复孵育。该模型假设dsb重新连接的速率随修复时间连续变化，并且在10 - 40 Gy范围内与剂量和剂量率无关。该模型还假设在4℃下dsb随剂量呈线性诱导，并且dsb诱导与照射期间的剂量率和温度无关。在4℃下对dsb诱导和修复速率的独立测量准确地预测了37℃照射后的dsb水平，在此期间这两种现象同时发生。
