Sl. Hickenbottom et al., Nuclear factor-kappa B and cell death after experimental intracerebral hemorrhage in rats, STROKE, 30(11), 1999, pp. 2472-2477
Background and Purpose-Nuclear factor-kappa B (NF-kappa B) is a ubiquitous
transcription factor that, when activated, translocates to the nucleus, bin
ds to DNA, and promotes transcription of many target genes. Its activation
has been demonstrated in chronic inflammatory conditions, cerebral ischemia
, and apoptotic cell death. The present study evaluated the presence and ac
tivation of NF-kappa B in relation to cell death surrounding intracerebral
hemorrhage (ICH).
Methods-Striatal ICH was induced in rats by the double blood injection meth
od. Animals were killed 2, 8, and 24 hours and 4 days after ICH. To examine
changes in NF-kappa B protein, Western blot was performed on brain extract
, We determined NF-kappa B activity using electrophoretic mobility shift as
say (EMSA) and immunohistochemistry, using an antibody that only recognizes
active NF-kappa B. DNA fragmentation was detected with terminal deoxynucle
otidyl transferase-mediated uridine 5'-triphosphate-biotin nick end-labelin
g (TUNEL) staining.
Results-Western blot analysis of the NF-kappa B p65 subunit showed that the
re was no difference in p65 protein levels in the control, 2-hour, 8-hour,
or 24-hour groups. However, ipsilateral perilesional samples from the 4-day
group revealed a 1.8- to 2.5-fold increase compared with the contralateral
hemisphere. Western blotting showed no differences in the inhibitor of NF-
kappa B, I kappa B alpha, in any group. EMSA showed 1.3-, 2.1-, and 3.6-fol
d increased NF-kappa B activation in the ipsilateral striatum from the 8-ho
ur, 24-hour, and 4-day groups, respectively, compared with the contralatera
l hemisphere. Immunohistochemistry, in which an activation-dependent anti-N
F-kappa B antibody was used, demonstrated perivascular NF-kappa B activatio
n as early as 2 hours after ICH with more generalized activation at 8 hours
, in agreement with the EMSA results, NF-kappa B activation colocalized to
cells containing fragmented DNA measured by TUNEL.
Conclusions-The present study suggests a relationship between NF-kappa B an
d the pathobiology of perilesional cell death after ICH.