Formation of the base modification 8-hydroxyl-2'-deoxyguanosine and DNA fragmentation following seizures induced by systemic kainic acid in the rat.
The formation of oxidative DNA damage as a consequence of seizures remains little explored. We therefore investigated the regional and temporal profile of 8-hydroxyl-2'-deoxyguanosine (8-OHdG) formation, a hallmark of oxidative DNA damage and DNA fragmentation in rat brain following seizures induced by systemic kainic acid (KA). Formation of 8-OHdG was determined via HPLC with electrochemical detection, and single- and double-stranded DNA breaks were detected using in situ DNA polymerase I-mediated biotin-dATP nick-translation (PANT) and terminal deoxynucleotidyl-transferase-mediated nick end-labeling (TUNEL), respectively. Systemic KA (11 mg/kg) significantly increased levels of 8-OHdG within the thalamus after 2 h, within the amygdala/piriform cortex after 4 h, and within the hippocampus after 8 h. Levels remained elevated up to sevenfold within these areas for 72 h. Smaller increases in 8-OHdG levels were also detected within the parietal cortex and striatum. PANT-positive cells were detected within the thalamus, amygdala/piriform cortex, and hippocampus 24-72 h following KA injection. TUNEL-positive cells appeared within the same brain regions and over a similar time course (24-72 h) but were generally lower in number. The present data suggest oxidative damage to DNA may be an early consequence of epileptic seizures and a possible initiation event in the progression of seizure-induced injury to DNA fragmentation and cell death.
Lan
J
J
Department of Neurology, University of Pittsburgh, Pennsylvania 15213, USA.
Henshall
D C
DC
Simon
R P
RP
Chen
J
J
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D053938:DNA Fragmentation; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000096:biosynthesis; D005821:Genetic Techniques; D020287:In Situ Nick-End Labeling; D007608:Kainic Acid; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012640:Seizures / Q000139:chemically induced / Q000235:genetics* / Q000378:metabolism*
D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine; D007608:Kainic Acid