Renan M J, Dowman P I
National Accelerator Centre, Faure, South Africa.
Radiat Res. 1989 Dec;120(3):442-55.
In this study, we have determined the radiosensitivity parameters of cells exposed in vitro to metallothionein-inducing agents. Three well-characterized tumor cell lines were chosen for investigation: HeLa, B16, and WHFIB. We have shown that exposure of cells in vitro to a heavy metal (cadmium), followed by irradiation, enhances cell survival for two out of three cell lines studied. As measured by the mean inactivation dose, the radioresistance increases by a factor of 1.6 for HeLa cells, 1.4 for WHFIB, and a negligible factor for B16 cells. An additional effect was noted when different classes of metallothionein inducers (such as serum factors, cadmium, and dexamethasone) were allowed to act together. Also, we found that the increase in radioresistance exhibits a peak at exposure times of approximately 10 h; longer exposure to inducing agents results in a reduction in radioresistance.
在本研究中，我们测定了体外暴露于金属硫蛋白诱导剂的细胞的放射敏感性参数。选择了三种特征明确的肿瘤细胞系进行研究：HeLa、B16和WHFIB。我们已经表明，体外将细胞暴露于重金属（镉），随后进行辐照，在所研究的三种细胞系中有两种细胞系的细胞存活率提高。通过平均失活剂量测量，HeLa细胞的放射抗性增加了1.6倍，WHFIB细胞增加了1.4倍，而B16细胞增加的倍数可忽略不计。当不同种类的金属硫蛋白诱导剂（如血清因子、镉和地塞米松）共同作用时，还观察到了额外的效应。此外，我们发现放射抗性的增加在暴露时间约为10小时时出现峰值；延长诱导剂暴露时间会导致放射抗性降低。
