Ochi T, Ishiguro T, Ohsawa M
Mutat Res. 1983 Nov;122(2):169-75. doi: 10.1016/0165-7992(83)90056-8.
A mechanism for the induction of DNA single-strand scissions in cultured Chinese hamster cells by cadmium chloride (CdCl2) was investigated by use of the technique of alkaline elution. Inducibility of DNA single-strand scissions by cadmium was examined under an aerobic or anaerobic culture condition. About 62% of the total cellular DNA was eluted throughout the filter within 10 h of elution time by treatment with 4 X 10(-5) M CdCl2 for 2 h in our usual aerobic medium. In contrast, no difference in elution profiles of DNA was observed between untreated control cells and the cells treated with CdCl2 in the anaerobic medium which was prepared by N2 gas bubbling of aerobic medium for 60 min. Furthermore, elution of DNA from cells treated with cadmium decreased markedly in the presence of superoxide dismutase (SOD) when compared with that in the absence of SOD. Inhibition of the cell growth by cadmium was significantly protected by the presence of SOD in the medium although the cell growth was not restored to the control level. These results indicate that active oxygen species participate in Cd-induced DNA single-strand scissions and also in the growth inhibition of the cells by the metal.
运用碱性洗脱技术，对氯化镉（CdCl₂）诱导培养的中国仓鼠细胞中DNA单链断裂的机制进行了研究。在需氧或厌氧培养条件下，检测镉对DNA单链断裂的诱导能力。在我们常用的需氧培养基中，用4×10⁻⁵M CdCl₂处理2小时，在洗脱10小时内，约62%的细胞总DNA从滤膜上洗脱下来。相比之下，通过向需氧培养基中通氮气60分钟制备的厌氧培养基中，未处理的对照细胞与用CdCl₂处理的细胞之间，DNA洗脱图谱没有差异。此外，与不存在超氧化物歧化酶（SOD）时相比，存在SOD时，镉处理细胞的DNA洗脱明显减少。尽管细胞生长未恢复到对照水平，但培养基中存在SOD可显著减轻镉对细胞生长的抑制作用。这些结果表明，活性氧参与了镉诱导的DNA单链断裂以及该金属对细胞生长的抑制作用。
