Witte I, Oetken G, Buschfort C, Hartmann A
Carl von Ossietzky-Universität, ICBM, Oldenburg, Germany.
Mutat Res. 1994 Jul;315(1):33-40. doi: 10.1016/0921-8777(94)90025-6.
The reduction of the colony-forming ability, the induction of DNA strand breaks and DNA repair were determined in human fibroblasts after treatment with tetracycline (TC) in the presence and absence of light. In all experiments human fibroblasts were more sensitive to incubations of TC in the light than in the dark. Induction of DNA single-strand breaks and DNA repair were detected in the cells after a 1-h incubation with TC under light but not in the dark. In contrast to these results, TC induced single-strand breaks in isolated PM2 DNA in the dark, however, to a lower extent than in the presence of light. In both cases strand break formation was totally suppressed by adding catalase. The formation of a TC-derived radical by ESR and a decomposition product by UV-vis spectroscopy was observed in the presence and absence of light; their rate of formation in the dark was much smaller than in the light.
在有光和无光条件下，用四环素（TC）处理人成纤维细胞后，测定其集落形成能力的降低、DNA链断裂的诱导和DNA修复情况。在所有实验中，人成纤维细胞在光照下对TC孵育的敏感性高于黑暗中。在光照下用TC孵育1小时后，细胞中检测到DNA单链断裂的诱导和DNA修复，但在黑暗中未检测到。与这些结果相反，TC在黑暗中可诱导分离的PM2 DNA单链断裂，但其程度低于光照条件下。在两种情况下，通过添加过氧化氢酶可完全抑制链断裂的形成。在有光和无光条件下均观察到通过电子自旋共振（ESR）形成的TC衍生自由基和通过紫外可见光谱形成的分解产物；它们在黑暗中的形成速率远小于光照下。
