Tofilon P J, Deen D F
Radiat Res. 1984 Jan;97(1):171-7.
We have studied the effect on sister chromatid exchange (SCE) induction in 9L rat brain tumor cells caused by combination treatment with BCNU and X rays. Over the dose and concentration ranges used in these experiments, BCNU induced relatively large numbers of SCEs, while X rays induced few SCEs. When cells were X irradiated immediately after BCNU treatment, the number of SCEs induced was greater than the number of SCEs expected by adding the number of SCEs induced by each agent alone; the number of SCEs induced as a result of this BCNU-X-ray interaction increased as the concentration of BCNU and/or dose of X rays increased. When the addition of bromodeoxyuridine was delayed from 0 to 16 hr after BCNU treatment, the number of SCEs induced declined to control levels by 16 hr. If X irradiation was delayed for up to 16 hr after BCNU treatment the same pattern of decrease was observed; the number of SCEs induced at each time point, however, was greater than that induced by BCNU and X rays alone. X irradiation from 0-16 hr before BCNU treatment produced the same number of SCEs as that produced by BCNU alone. Thus the SCE assay is capable of detecting a drug-X-ray interaction in mammalian cells and provides a sensitive means of studying the sequencing and timing that leads to the interaction.
我们研究了卡氮芥（BCNU）与X射线联合处理对9L大鼠脑肿瘤细胞姐妹染色单体交换（SCE）诱导的影响。在这些实验所使用的剂量和浓度范围内，BCNU诱导产生相对大量的SCE，而X射线诱导产生的SCE较少。当细胞在BCNU处理后立即接受X射线照射时，诱导产生的SCE数量大于单独使用每种试剂诱导产生的SCE数量之和；由于这种BCNU与X射线的相互作用而诱导产生的SCE数量随着BCNU浓度和/或X射线剂量的增加而增加。当在BCNU处理后将溴脱氧尿苷的添加时间从0小时延迟至16小时时，诱导产生的SCE数量在16小时时降至对照水平。如果在BCNU处理后将X射线照射延迟长达16小时，也观察到相同的下降模式；然而，在每个时间点诱导产生的SCE数量大于单独使用BCNU和X射线诱导产生的数量。在BCNU处理前0 - 16小时进行X射线照射产生的SCE数量与单独使用BCNU产生的数量相同。因此，SCE检测能够检测哺乳动物细胞中的药物与X射线相互作用，并提供一种研究导致这种相互作用的顺序和时间安排的灵敏方法。
