Study on oxidative DNA damage and repair enzyme in acute and chronic renal disease

我们检测了大鼠肾脏I/R损伤时DNA氧化损伤的主要类型8-oxo-dG的含量，并研究了编码8-oxoguanine DNA糖基化酶的OGG 1基因的表达水平。高效液相色谱与MS/MS分析的核DNA显示立即积累的8-oxo-dG的核DNA制备的皮质和OM的肾I/R后1小时，和免疫组化分析表明，立即积累的8-oxo-dG的肾小管细胞的细胞核中的皮质和OM。仅在皮质-髓质和OM中观察到抗8-oxo-dG的细胞质染色延迟增加，其中近端肾小管细胞的细胞质染色高于远端肾小管细胞。线粒体DNA中代表8-oxo-dG的胞质染色水平在I/R后6 h达到峰值，并先于OM中近端小管细胞坏死， ...更多信息 硒保护试验显示正常肾组织中OGG 1 mRNA水平较高，仅OM在缺血3 h内表达下降，缺血1 ~ 7 d后，皮质和OM中OGG 1 mRNA水平均升高。原位杂交显示OM肾小管中OGG 1 mRNA表达水平高于正常肾皮质，但在I/R后3 h内迅速下降。因此，在线粒体DNA中，而不是在核DNA中的8-oxo-dG的积累是可能参与的致病反应，如坏死的肾小管细胞在I/R损伤的肾脏，连同改变水平的OGG 1 expression. Further，我们研究的参与8-oxo-dG顺铂诱导的肾小管细胞死亡，在体内和体外。顺铂诱导肾小管细胞死亡前8-oxo-dG蓄积，联合应用羟自由基清除剂DMTU可抑制8-oxo-dG蓄积和肾小管损伤，在5/6肾切除大鼠肾脏中未见明显蓄积。少

We examined the contents of 8-oxo-2'-deoxyguanosine (8-oxo-dG), which is a major type of oxidative damage in DNA, in the rat kidney during I/R injury, and also investigated the expression level of the OGG1gene encoding the 8-oxoguanine DNA glycosylase. High-performance liquid chromatography with an MS/MS analysis of the nuclear DNA revealed an immediate accumulation of 8-oxo-dG in the nuclear DNA prepared from the cortex and OM of the kidney 1 h after I/R, and an immunohistochemical analysis demonstrated the immediate accumulation of 8-oxo-dG in the nuclei of renal tubular cells both in the cortex and OM. A delayed increase of cytoplasmic staining with anti-8-oxo-dG was observed only in the cortico-medulla and OM, where the cytoplasmic staining in the proximal tubular cells is higher than in the distal tubular cells. The level of cytoplasmic staining representing 8-oxo-dG in mitochondrial DNA, peaked at 6 h after I/R and preceded the necrosis of proximal tubular cells in the OM, An Rna … More se protection assy showed a high level of OGG1 mRNA in the normal kidney, and the level decreased within 3 h only in the OM, and increased thereafter 1 to 7 days of I/R both in the cortex and OM. In situ hybridization showed higher levels of OGG1 mRNA expression in the renal tubules in the OM than in the cortex of the normal kidney, which decreased rapidly within 3 h of I/R. Thus, the accumulation of 8-oxo-dG in the mitochondrial DNA rather than in nuclear DNA is likely to be involved in the pathogenic responses such as necrosis of renal tubular cells during I/R injury of the kidney, together with an altered level of OGG1 expression.Furthermore, we examined the involvement of 8-oxo-dG in cisplatin-induced renal tubular cell death, in vivo and in vitro. Cisplatin induced accumulation of 8-oxo-dG in renal tubular cells before cell death, and co-administration of DMTU, a scavenger of hydroxyl radicals, inhibited such accumulation and renal tubular damage.In the kidney of 5/6 nephrectomized rats, obvious accumulation of 8-oxo-dG was not observed. Less