重铬酸钾和谷胱甘肽作用致小牛胸腺DNA损伤的原子力显微镜研究

Study of DNA damage induced by potassium dichromate and glutathione with atomic force microscope

目的研究重铬酸钾和谷胱甘肽对小牛胸腺DNA的损伤。方法利用原子力显微镜、紫外光谱两种分析方法观察DNA的超微结构变化和吸收光谱的改变。结果单一重铬酸钾不能诱导DNA断裂,但将重铬酸钾和谷胱甘肽按一定比例和浓度混合同时作用于DNA时,则可以诱导小牛胸腺DNA断裂。紫外-可见吸收光谱分析也得到同样的结果,当重铬酸钾和谷胱甘肽共同作用DNA时,其最大吸收峰呈增色效应。结论从形态学和光谱学角度佐证了谷胱甘肽在引发铬(VI)化合物发生还原反应产生多种中间产物并导致人体细胞癌变中有重要作用。

Objective To observe calf thymus DNA damage induced by potassium dichromate in combination with glutathione （GSH）. Methods Atomic force microscope and ultraviolet spectrum （UV） were used to observe the alterations of the DNA ultrastructure and absorption spectrum. Results Atomirc force microscopy revealed no breaks of the DNA strand in response to treatment with potassium dichromate alone, but when coupled with GSH at proper concentrations, potassium dichromate induced alterations in the DNA structure and DNA fragmentation. UV examination also confirmed these findings by showing increased absorption intensity of the maximum UV peak following combined treatment of the DNA with potassium dichromate and GSH. Conclusion These morphological and spectrographic evidences verified the important role of GSH in mediating the generation of various tumor-inducing intermediate products of potassium dichromate.