噻嗪染料加光介导DNA中8-羟基鸟嘌呤的形成。

Mediation of 8-hydroxy-guanine formation in DNA by thiazin dyes plus light.

作者信息

Floyd R A, West M S, Eneff K L, Schneider J E

机构信息

Molecular Toxicology Research Group, Oklahoma Medical Research Foundation, Oklahoma City 73104.

出版信息

Free Radic Biol Med. 1990;8(4):327-30. doi: 10.1016/0891-5849(90)90097-3.

DOI:10.1016/0891-5849(90)90097-3

PMID:2379862

Abstract

We have discovered that methylene blue plus light mediates the formation of 8-OHdG in DNA. Methylene blue is one of several thiazin dyes and we report here that the other thiazin dyes tested, in combination with white light, are effective in mediating 8-OHdG formation in DNA. The effectiveness of light plus the thiazin dyes in forming 8-OHdG in DNA were as follows: methylene blue greater than azure B greater than azure A greater than toluidine blue greater than thionin. Two other compounds tested; riboflavin and fuschin acid, in combination with light, caused formation of very little, if any, 8-OHdG in DNA. Thiazin dye mediated formation of 8-OHdG in DNA was not inhibited by the spin trap alpha-phenyl-t-butyl nitrone, which supports our previous observations that oxygen free radical scavengers did not inhibit methylene blue plus light mediated 8-OHdG formation in DNA. Ascorbate addition to methylene blue plus DNA, in the absence of light, was ineffective in mediating 8-OHdG formation in DNA.

摘要

我们发现亚甲蓝加光可介导DNA中8-羟基脱氧鸟苷（8-OHdG）的形成。亚甲蓝是几种噻嗪染料之一，我们在此报告，所测试的其他噻嗪染料与白光结合，在介导DNA中8-OHdG的形成方面是有效的。光加噻嗪染料在DNA中形成8-OHdG的有效性如下：亚甲蓝大于天青B大于天青A大于甲苯胺蓝大于硫堇。测试的另外两种化合物；核黄素和品红酸，与光结合，在DNA中几乎不引起8-OHdG的形成（如果有形成的话）。噻嗪染料介导的DNA中8-OHdG的形成不受自旋捕获剂α-苯基叔丁基硝酮的抑制，这支持了我们之前的观察结果，即氧自由基清除剂不会抑制亚甲蓝加光介导的DNA中8-OHdG的形成。在无光条件下，向亚甲蓝加DNA中添加抗坏血酸在介导DNA中8-OHdG的形成方面无效。