DNA氧化损伤模型的构建

A MODEL OF OXIDATIVE DAMAGE ON DNA

目的 :探索Fenton反应 (Fe2 ++H2 O2 →Fe3++·OH +OH-)氧化损伤DNA的实验条件。方法∶气相色谱/质谱分析法探索Fenton反应对DNA中 8-羟基鸟嘌呤含量的影响 ,观察经不同浓度的H2 O2 和Fe2 +及不同时间处理后DNA样品中 8-羟基鸟嘌呤含量的改变。结果∶Fenton反应显著升高DNA中 8-羟基鸟嘌呤含量。 8-羟基鸟嘌呤含量随H2 O2 浓度的改变而呈三相变化∶H2 O2 浓度在 0 .0 8～ 5mmol/L范围时 ,8-羟基鸟嘌呤含量随H2 O2 浓度的升高而升高 ;H2 O2 浓度在 5～ 2 0mmol/L范围时 ,其含量随H2 O2 浓度的升高而减少 ;H2 O2 浓度在 2 0～ 80mmol/L范围时 ,8-羟基鸟嘌呤含量维持在一个较对照组高的水平 ,而不随H2 O2 浓度的改变而发生明显的改变。增加Fe2 +浓度或延长反应时间均可提高DNA中 8-羟基鸟嘌呤的含量。

Objective:To explore the experimental conditions of oxidative damage on DNA by Fenton's reaction.Methods:The effect of Fenton's reaction on the production of 8-hydroxyguanine in DNA was investigated with GC/MS,and the content of this modified base in DNA was analyzed when DNA samples were treated with different concentrations of H 2O 2and Fe 2+ and different times of reaction.Results:Fenton's reaction increased significantly the contents of 8-hydroxyguanine in DNA.Its yield in DNA showed three-phase alteration when DNA is treated with serial concentrations of H 2O 2:the higher were H 2O 2 concentrations in the range from 0.08mmol/L to 5mmol/L,the higher would be the yield of 8-hydroxyguanine;however,as H 2O 2 concentration became higher,in the range from 5 mmol/L to 20mmol/L,the yield of 8-hydroxyguanine was lowered;its yield remained higher than that in control,while no significant change was observed with the increase of H 2O 2 in the range from 20mmol/L to 80mmol/L.The yield of 8-hydroxyguanine in DNA was increased when Fe 2+ concentrations in Fenton's reaction was raised or reaction time prolonged.Conclusions:A model of oxidative damage on DNA by Fenton's reaction was established.