老龄大鼠晶状体DNA损伤及DNA修复酶表达的变化

Purpose：To determine if there is increased mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) damage with age in the lenses of rats. We also explored the predominant Base Excision Repair (BER) enzymes: 8-oxoguanine DNA glycosylase 1 (OGG1) and AP endonuclease 1 (APE1) in the lens. Methods：The methods used by this study include the selection of male Wistar rats in each group (2 months old, 16 months old and 26 months old) in the group. We examined mtDNA and nDNA damage with a quantitative polymerase chain reaction (QPCR) assay. We also studied the gene expression of mRNA and protein in these key BER enzymes with real time-polymerase chain reaction (RT-PCR) and western blot analysis. Results：There was an increase in oxidative DNA damage, which exists primarily in the mtDNA. The amount of 8-OHdG in DNA was significantly increased with age. Our experiments demonstrated that the gene expression of mRNA and protein in these key BER enzymes decreased with age. Conclusions：The gene expression of mRNA and protein in these key BER enzymes decreased with age, which caused a decrease in the repairing capability of the mtDNA and the accumulation of mtDNA damage. The increased mtDNA damage and decreased expression of BER enzymes may cause a "vicious cycle" of oxidative stress that contributes to the accumulation of mtDNA mutations and age-related cataract pathogenesis.