TY - JOUR
T1 - In situ detection of neuronal DNA strand breaks using the Klenow fragment of DNA polymerase I reveals different mechanisms of neuron death after global cerebral ischemia
AU - Jin, Kunlin
AU - Chen, Jun
AU - Nagayama, Tetsuya
AU - Chen, Minzhi
AU - Sinclair, Jennifer
AU - Graham, Steven H.
AU - Simon, Roger P.
PY - 1999
Y1 - 1999
N2 - Ischemic cell injury in the brain may involve a cascade of programmed cell death. DNA damage may be either a catalyst or a consequence of this cascade. Therefore, the induction of DNA strand breaks in the rat brain following transient global ischemia was examined using (a) the Klenow labeling assay, identifying DNA single-strand breaks (SSBs) or double-strand breaks (DSBs) with protruding 5' termini, and (b) terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL), detecting DNA DSBs with protruding 3' termini or blunt ends. Klenow-positive staining occurred within 2 h of reperfusion and increased with increasing durations of reperfusion. DNA damage detected with the Klenow labeling assay preceded that of TUNEL expression in the caudate putamen, reticular thalamus, thalamus, and cortex. However, in CA1, DNA SSBs were not detected until 72 h of reperfusion and occurred simultaneously with DSBs. Thus, the time course and fragmentation characteristics of DNA damage differ between the hippocampal CA1 and other selectively vulnerable brain regions. This distinct pattern suggests that the delayed neuronal death in CA1 following transient global ischemia may occur via an apoptotic mechanism different from that of other brain regions.
AB - Ischemic cell injury in the brain may involve a cascade of programmed cell death. DNA damage may be either a catalyst or a consequence of this cascade. Therefore, the induction of DNA strand breaks in the rat brain following transient global ischemia was examined using (a) the Klenow labeling assay, identifying DNA single-strand breaks (SSBs) or double-strand breaks (DSBs) with protruding 5' termini, and (b) terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL), detecting DNA DSBs with protruding 3' termini or blunt ends. Klenow-positive staining occurred within 2 h of reperfusion and increased with increasing durations of reperfusion. DNA damage detected with the Klenow labeling assay preceded that of TUNEL expression in the caudate putamen, reticular thalamus, thalamus, and cortex. However, in CA1, DNA SSBs were not detected until 72 h of reperfusion and occurred simultaneously with DSBs. Thus, the time course and fragmentation characteristics of DNA damage differ between the hippocampal CA1 and other selectively vulnerable brain regions. This distinct pattern suggests that the delayed neuronal death in CA1 following transient global ischemia may occur via an apoptotic mechanism different from that of other brain regions.
KW - Brain
KW - DNA strand breaks
KW - Ischemia
KW - Klenow fragment-Terminal deoxynucleotidyl transferase
KW - Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling
UR - http://www.scopus.com/inward/record.url?scp=0033048622&partnerID=8YFLogxK
U2 - 10.1046/j.1471-4159.1999.0721204.x
DO - 10.1046/j.1471-4159.1999.0721204.x
M3 - Article
C2 - 10037493
AN - SCOPUS:0033048622
SN - 0022-3042
VL - 72
SP - 1204
EP - 1214
JO - Journal of Neurochemistry
JF - Journal of Neurochemistry
IS - 3
ER -