Transient global
ischemia continues to be an important clinical problem with limited treatment options. The present study aimed to investigate the possible protective effects of
celecoxib [a selective
cyclooxygenase (COX-2) inhibitor] and
N-omega-nitro-L-arginine methyl ester (
L-NAME) [a nonselective
nitric oxide synthase (NOS) inhibitor] against global
ischemia-reperfusion (IR) induced biochemical and histological alterations in the rat hippocampus. Global
ischemia was induced by bilateral clamping of the common carotid arteries for 60 minutes. Hippocampal cysteinyl
aspartate-specific protease-3 (caspase-3) activity,
nitrite/
nitrate contents (NOX), as well as COX-2 immunoreactivity in the hippocampal Cornu Ammonis 1 (CA1) subregion were dramatically increased 24 hours after global
ischemia. After 72-hour of reperfusion,
ischemia induced a selective, extensive neuronal loss in the hippocampus CA1 subregion.
Celecoxib (3 and 5 mg/kg, intraperitoneally; i.p.), administered 30 minutes before
ischemia and at 6, 12, and 22 hours of 24-hour reperfusion, caused significant reductions in hippocampal
caspase-3 activity as well as the number of COX-2 immunoreactive (COX-2 ir) neurons in the CA1 subregion. Further,
celecoxib (3 or 5 mg/kg, i.p.), administered 30 minutes before
ischemia and at 6, 12, 22, and 48 hours of 72-hour reperfusion, provided a notable histological protection of hippocampal CA1 neurons. Meanwhile,
L-NAME (3 mg/kg, i.p.), administered twice (immediately after
ischemia and 45 minutes after starting the reperfusion period), effectively reduced the elevated NOX level, decreased hippocampal
caspase-3 activity and COX-2 immumoreactivity, and ameliorated
ischemia-induced damage in the hippocampal CA1 subregion. The present study indicates that
celecoxib and
L-NAME might be
neuroprotective agents of potential benefit in the treatment of
cerebral ischemia.