Induction of cyclooxygenase-2 in the rat brain after a mild episode of focal ischemia without tissue inflammation or neural cell damage

Cyclooxygenase-2, a key enzyme in prostanoid synthesis, is induced by infla mmatory stimuli and it is associated with cell death after cerebral ischemi a. Here we evaluated whether cyclooxygenase-2 was induced after a short (10 -min) episode of focal ischemia, mild enough not to cause inflammation or c ell death. One-hour ischemia leading to brain infarct was studied for compa rative purposes. Induction of cyclooxygenase-2 mRNA and protein was detecte d after both 10-min and l-h ischemia. However, signs of edema were only app arent after 1-h, but not 10-min ischemia, and only rats subjected to 1-h is chemia had developed brain infarct at 4 days. Therefore, cyclooxygenase-2, not linked with neural cell death or inflammation, is induced after focal i schemia. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.