hOGG1基因低表达对DNA氧化损伤及修复的影响初探

Preliminary Study on the Effect of Down-regulated hOGG1 Gene Expression on DNA Damage and Repair

背景与目的:初步探讨采用核酶技术获得的hOGG1基因低表达的细胞对氧化剂诱导的DNA氧化损伤与修复作用的影响。材料与方法:以A549细胞和通过稳定转染hOGG1核酶而获得的hOGG1低表达的A549_R细胞为研究对象,分别以重铬酸钾和过氧化氢为受试物,比较两种细胞DNA损伤与修复的差异。彗星试验检测不同浓度受试物作用下两种细胞的彗星细胞率和DNA迁移长度;改良彗星试验比较两种细胞在去除受试物后孵育0、30、60、120和180min时的修复情况。结果:重铬酸钾和过氧化氢对A549_R细胞的DNA损伤效应敏感,在一些浓度下其彗星细胞率和DNA迁移长度明显高于A549细胞(P<0.05);A549_R细胞的DNA修复能力显著低于A549细胞(P<0.05)。结论:hOGG1基因的低表达可以增加细胞对氧化剂诱导的DNA损伤的敏感性,降低细胞DNA的修复能力。

BACKGROUND ＆ AIM： Preliminary study on the effect of down-regulation hOGG1 gene expression obtained by ribozyme on DNA damage and repair. MATERIAL AND METHODS： To compare the diference of DNA oxidative damage and repair between A549 cells and A549-R cells containing down-regulated hOGG1 gene expression constructed by ribozyme technique. The two kinds of ceils were exposed to potassium dichromate and hydrogen peroxide. Comet cell rate and DNA migration length of both kinds of ceils were tested under different substrate concentrations of the oxidants. After the oxidants were removed, the cells were incubated for 0, 30, 60, 120 and 180 min. The same indexes were tested by modified comet assay, RESULTS： A549-R cells were more sensitive to the effect of DNA oxidative damage than A549 ceils under specific concentrations of potassium dichromate and hydrogen peroxide （P 〈0.05）, and the ability of DNA repair of A549-R cells was significantly lower than that of A549 cells （P〈0.05） CONCLUSION： The down-regulated expression of hOGG1 gene could increase the sensitivity of DNA damage and decrease the ability in DNA repair in A549 cells exposed to oxidants.