The widespread benefit of thrombolysis has been emphasized, but relatively little is known about
reperfusion injury. The purpose of this study is to evaluate the difference in
nitrotyrosine formation and
infarct volume between permanent and transient focal
ischemia in rats. Permanent (n = 14) or transient (n = 12) focal
ischemia was induced by permanent or 2-hour occlusion of the middle cerebral artery, respectively, with the permanent
ligation of the bilateral common carotid arteries in Sprague-Dawley rats. In both models all animals were killed 24 hours after the start of occlusion. The ratio of
nitrotyrosine in the peri-
infarct and core-of-
infarct regions in transient focal
ischemia was significantly higher than in permanent focal
ischemia (P < .01).
Infarct volume in the cortex, but not caudoputamen or whole brain, was significantly larger in transient
ischemia than in permanent
ischemia (P < .05), with a significant expansion of
brain swelling. These results may reflect the higher production of
superoxide and
nitric oxide owing to reperfusion, and suggest the need to administer
neuroprotective drugs such as
anti-oxidants as well as
thrombolytic agents in the treatment of acute ischemic cerebral damage.