Induction of oxidative DNA damage in the peri-infarct region after permanent focal cerebral ischemia
Induction of oxidative DNA damage in the peri-infarct region after permanent focal cerebral ischemia
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DOI：
10.1046/j.1471-4159.2000.0751716.x
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发表时间：
2000-10-01
影响因子：
4.7
通讯作者：
Chen, J
中科院分区：
文献类型：
--
作者：
Nagayama, T;Lan, J;Chen, J
为了研究氧化性DNA损伤在局灶性脑缺血再灌注缺失中的作用，我们研究了永久性大脑中动脉闭塞（MCAO）大鼠模型的DNA碱基和链损伤，定量测定了MCAO后4-72 h脑核DNA提取物中8-羟基-2′-脱氧鸟苷（8-OHdG）和无尿嘧啶/无嘧啶基基位点（AP位点）的含量，这些位点是氧化性DNA损伤的标志。利用原位DNA聚合酶i介导的生物素- datp缺口翻译（PANT）和末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）分别在冠状脑切片上检测到DNA单链和双链断裂，MCAO后16-72小时额叶皮层8-OHdG和AP位点水平显著升高，代表梗死周围区域。但在尾核-壳核和顶叶皮质的缺血核心区域，水平没有显著变化。喘气,TUNEL-positive细胞开始检测4 - 8 h caudate-putamen MCAO后顶叶皮层和达到最大水平在72 h。裤子,TUNEL-positive细胞也发现16 - 72 h MCAO后外侧额叶皮质梗死边界内许多细胞还显示colocalization DNA单链断裂和DNA碎片,相比之下,PANT-positive细胞水平仅是暂时性的增加(MCAO后16 h)的内侧额叶皮质,梗塞区：远离梗塞区的区域这些数据表明，在脑梗死周围区域，以碱基和链损伤形式对核DNA的氧化损伤可能是永久性局灶性缺血后继发性脑损伤扩大的重要原因。
To address the role of oxidative DNA damage in focal cerebral ischemia lacking reperfusion, we investigated DNA base and strand damage in a rat model of permanent middle cerebral artery occlusion (MCAO), Contents of 8-hydroxyl-2'-deoxyguanosine (8-OHdG) and apurinic/apyrimidinic abasic sites (AP sites), hallmarks of oxidative DNA damage, were quantitatively measured in nuclear DNA extracts from brains obtained 4-72 h after MCAO, DNA single- and double-strand breaks were detected on coronal brain sections using in situ DNA polymerase I-mediated biotin-dATP nick-translation (PANT) and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL), respectively, Levels of 8-OHdG and AP sites were markedly elevated 16-72 h following MCAO in the frontal cortex, representing the peri-infarct region, but levels did not significantly change within the ischemic core regions of the caudate-putamen and parietal cortex. PANT- and TUNEL-positive cells began to be detectable 4-8 h following MCAO in the caudate-putamen and parietal cortex and reached maximal levels at 72 h. PANT- and TUNEL-positive cells were also detected 16-72 h after MCAO in the lateral frontal cortex within the infarct border, where many cells also showed colocalization of DNA single-strand breaks and DNA fragmentation, In contrast, levels of PANT-positive cells alone were transiently increased (16 h after MCAO) in the medial frontal cortex, an area distant from the infarct zone. These data suggest that within periinfarct brain regions, oxidative injury to nuclear DNA in the form of base and strand damage may be a significant and contributory cause of secondary expansion of brain damage following permanent focal ischemia.