Skare J A, Wong T K, Evans B L, Cody D B
Mutat Res. 1986 Oct;172(1):77-87. doi: 10.1016/0165-1218(86)90109-6.
Sodium fluoride (NaF) was assayed for the induction of DNA-repair synthesis in WI-38 human diploid fibroblasts and in primary cultures of rat hepatocytes. DNA-repair synthesis in non-replicating DNA was measured by ultracentrifugation of density-labeled DNA in CsCl gradients. When this method was used, NaF did not induce DNA-repair synthesis in either of these cell types. However, when NaF was assayed for induction of unscheduled DNA synthesis (UDS) in rat hepatocytes by autoradiography, an increased net nuclear grain count was observed. Because the autoradiographic results were not confirmed by density-gradient ultracentrifugation of hepatocyte DNA, which is a more definitive technique, it is doubtful whether the autoradiographic results actually represent DNA-repair synthesis. Modifications of the UDS/autoradiography protocol to include more extensive washing resulted in no UDS response. Published reports (Hellung-Larsen and Klenow, 1969; Srivastava et al., 1981) describe the formation of precipitable complexes of Mg2+, F-, and [3H]thymidine triphosphate which suggests that autoradiographic measurement of UDS may lead to artifacts when testing NaF unless extensive washing of the cultures is employed.
对氟化钠（NaF）进行了检测，以观察其对WI-38人二倍体成纤维细胞和大鼠肝细胞原代培养物中DNA修复合成的诱导作用。通过在CsCl梯度中对密度标记的DNA进行超速离心来测量非复制性DNA中的DNA修复合成。当使用这种方法时，NaF在这两种细胞类型中均未诱导DNA修复合成。然而，当通过放射自显影检测NaF对大鼠肝细胞中DNA非常规合成（UDS）的诱导作用时，观察到净核颗粒计数增加。由于更具权威性的肝细胞DNA密度梯度超速离心结果并未证实放射自显影结果，因此放射自显影结果是否真的代表DNA修复合成值得怀疑。对UDS/放射自显影实验方案进行修改，增加更广泛的洗涤步骤后，未观察到UDS反应。已发表的报告（Hellung-Larsen和Klenow，1969年；Srivastava等人，1981年）描述了Mg2+、F-和[3H]胸苷三磷酸可沉淀复合物的形成，这表明在检测NaF时，除非对培养物进行广泛洗涤，否则UDS的放射自显影测量可能会导致假象。
