增龄大鼠心肌线粒体DNA损伤及DNA修复酶γ表达的变化  

Expression changes in DNA polymerase γ and mitochondrial DNA damage in aging rat hearts

作　　者：张兰[1] 张毅[2] 刘娴[1] 李赫[1] 顾金霞[1] 肖模超[1] 王晓云[1] 

机构地区：[1]哈尔滨医科大学附属第四医院心内一科,黑龙江哈尔滨150021 [2]哈尔滨医科大学附属第一医院眼科,黑龙江哈尔滨150001

出　　处：《心脏杂志》2012年第1期23-27,共5页Chinese Heart Journal

摘　　要：目的:探讨大鼠增龄过程中心肌组织DNA损伤和DNA修复酶表达的变化。方法:从不同月龄的大鼠心肌组织中提取DNA、RNA及蛋白。采用定量多聚酶链反应(Q-PCR)检测心肌DNA损伤;用RT-PCR和Western blot检测DNA修复酶γ(Polγ)表达的变化。用ELISA法检测DNA内8羟基脱氧鸟苷(8-OHdG)的水平。结果:随着鼠龄的增长,大鼠心肌组织中核DNA(nDNA)损伤不明显,线粒体DNA(mtDNA)损伤严重,DNA内8-OHdG的水平增加,Polγ的表达下降。结论:随着鼠龄的增长,大鼠心肌组织中DNA修复酶Polγ的表达下降,mtDNA损伤增加。DNA损伤与DNA修复能力下降间会引起恶性循环,最终可导致DNA损伤的增加加快心脏衰老。AIM：To investigate whether mitochondrial DNA（mtDNA） and nuclear DNA（nDNA） damage increase with age in rat hearts and to explore the changes of DNA polymerase γ（Polγ） in rat hearts.METHODS：Total DNA,RNA and proteins of hearts were isolated.Damages of mtDNA and nDNA were examined with quantitative polymerase chain reaction（qPCR） assay combined with EvaGreen.Gene expressions of mRNA and protein in Polγ were detected with real-time polymerase chain reaction（RT-PCR） and Western blot analysis,and the levels of 8-hydroxy-2′-deoxy-guanosine（8-OHdG） in DNA were studied with ELISA assay.RESULTS：Oxidative DNA damage increased,primarily in mtDNA.The amount of 8-OHdG in DNA significantly increased with age and gene expression of mRNA and protein in Polγ decreased with age.CONCLUSION：The gene expression of mRNA and protein in the key BER enzymes decreases with age,which causes a decrease in the repair capability of the mtDNA and the accumulation of mtDNA damage.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 cardiofailure pathogenesis.

关 键 词：线粒体DNA DNA修复酶 心肌 

分 类 号：R542.2[医药卫生—心血管疾病]