McHugh P J, Knowland J
Department of Biochemistry, University of Oxford, UK.
Photochem Photobiol. 1997 Aug;66(2):276-81. doi: 10.1111/j.1751-1097.1997.tb08655.x.
We describe an in vitro approach to assessing the potential genotoxicity of illuminated sunscreens. The photomutagenic sunscreen Padimate-O attacks DNA on illumination with simulated sunlight, producing strand breaks and lesions that are labile to N,N'-dimethylethylenediamine but few, if any, cyclobutane dimers or other direct photoproducts. The damage can be completely suppressed by the free radical quenchers Tris, ethanol, mannitol and dimethylsulfoxide, which is commonly used as a solvent in conventional photomutagenicity assays. Using a genetic reversion assay that depends on regenerating beta-galactosidase activity in photodamaged plasmids we find that GC base pairs are particularly susceptible to attack by Padimate-O.
我们描述了一种体外方法，用于评估光照下防晒霜的潜在遗传毒性。光致突变性防晒霜对氨基苯甲酸二乙氨基乙醇酯在模拟阳光照射下会攻击DNA，产生链断裂和对N，N'-二甲基乙二胺不稳定的损伤，但几乎没有环丁烷二聚体或其他直接光产物。自由基淬灭剂三羟甲基氨基甲烷、乙醇、甘露醇和二甲基亚砜可以完全抑制这种损伤，二甲基亚砜在传统的光致突变性试验中常用作溶剂。使用一种依赖于在光损伤质粒中再生β-半乳糖苷酶活性的遗传回复试验，我们发现GC碱基对特别容易受到对氨基苯甲酸二乙氨基乙醇酯的攻击。
