经碱基切除修复的氧化性DNA损伤与肝癌的发生

Oxidative DNA damage repair via base excision repair pathway and hepatocarcinogenesis

在生物体内如果过氧化物的产生和消除存在不平衡均会导致氧化应激的发生．很多病理生理状况跟氧化应激有密切的关系。氧化应激产生的活性氧．可诱发DNA碱基发生化学修饰，在嘌呤残基的C-8位置和DNA整合，形成8-羟基二羟鸟嘌呤并进-步氧化形成8-羟基鸟嘌呤（8-OHdG）。8-OHdG是一种主要的DNA氧化损伤产物，经碱基切除修复通路来完成修复，若不及时修复，则参与癌变的发生。

Oxidative stress occurs when there is an imbalance in the generation and removal of radical species within an organism. ROS has been associated with a variety of patho-physiolgic conditions. Oxidative stress can produce ROS; ROS induce a variety of lesions in DNA, including chemical alterations. Oxidation of guanine residues at the 8 - position to produce 8 - hydroxy- 2＇- deoxyguanosine further oxidized guanine forms 8- hydroxydeoxyguanine （8-OHdG）. 8-hydroxydeoxyguanosine （8-OHdG） is a biomarker of oxidative DNA damage and repair via base excision repair . If not being promptly repaired ,it can participate in hepatocarcinogenesis.