Induction of oxidative DNA damage in the peri-infarct region after permanent focal cerebral ischemia.
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 caudateputamen 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 peri-infarct 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.
Nagayama
T
T
Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA.
Lan
J
J
Henshall
D C
DC
Chen
D
D
O'Horo
C
C
Simon
R P
RP
Chen
J
J
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000818:Animals; D001783:Blood Flow Velocity; D001921:Brain / Q000098:blood supply / Q000378:metabolism / Q000473:pathology; D001923:Brain Chemistry; D020520:Brain Infarction / Q000378:metabolism* / Q000473:pathology; D002545:Brain Ischemia / Q000378:metabolism* / Q000473:pathology; D002560:Cerebrovascular Circulation; D019457:Chromosome Breakage; D004247:DNA / Q000737:chemistry; D004249:DNA Damage / Q000502:physiology*; D053938:DNA Fragmentation; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000032:analysis; D004195:Disease Models, Animal; D020287:In Situ Nick-End Labeling; D020244:Infarction, Middle Cerebral Artery; D008297:Male; D018384:Oxidative Stress; D051381:Rats; D017207:Rats, Sprague-Dawley
D000080242:8-Hydroxy-2'-Deoxyguanosine; D004247:DNA; D003849:Deoxyguanosine