title: Reperfusion-induced temporary appearance of therapeutic window in penumbra after 2 h of photothrombotic middle cerebral artery occlusion in rats.
abstract: To explore the effects of reperfusion on evolution of focal ischemic injury, spontaneously hypertensive male rats were subjected to photothrombotic distal middle cerebral artery occlusion (MCAO) with or without YAG laser-induced reperfusion. The volume of fodrin breakdown zone, water content, and brain tissue levels of sodium (Na(+)) and potassium (K(+)) were measured in the ischemic core and penumbra. Reperfusion attenuated fodrin breakdown, and the volume containing fodrin breakdown product at 3 h after reperfusion (5 h after MCAO) (30+/-7 mm(3)) was significantly smaller than the 42+/-3 mm(3) of the permanent occlusion group. After 3 to 6 h of ischemia, Na(+) increased, and K(+) decreased in the ischemic core. Reperfusion after 2 h of MCA occlusion did not mitigate the ischemia-induced changes in brain tissue electrolytes and water content at 3 to 6 h of ischemia. Even in reperfusion after comparatively long periods of occlusion where brain infarction size, assessed 3 days after MCAO, was not significantly reduced by reperfusion, and the precipitating indicators of the ischemic core (Na(+), K(+), water content) did not improve, temporary improvement or a delay in progression of ischemic injury was discernible in the penumbra. These results indicate the possibility that treatment with reperfusion is permissive to the effects of neuroprotection.
authors.affiliation: Laboratory for Neurochemistry, Center for Emotional and Behavioral Disorders, National Hospital Organization, Hizen Psychiatric Center, Saga, Japan. hyao@hizen2.hosp.go.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yao
authors.forename: Narihiko
authors.initials: N
authors.lastname: Yoshii
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Akira
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Nakahara
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology; D001929:Brain Edema / Q000209:etiology / Q000473:pathology / Q000517:prevention & control; D002352:Carrier Proteins / Q000378:metabolism; D002540:Cerebral Cortex / Q000098:blood supply / Q000473:pathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D004195:Disease Models, Animal; D004573:Electrolytes / Q000378:metabolism; D005456:Fluorescent Dyes / Q000008:administration & dosage; D020244:Infarction, Middle Cerebral Artery / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D053685:Laser Therapy; D007834:Lasers / Q000009:adverse effects; D008297:Male; D008840:Microfilament Proteins / Q000378:metabolism; D018696:Neuroprotective Agents / Q000008:administration & dosage*; D051381:Rats; D011918:Rats, Inbred SHR; D015424:Reperfusion / Q000295:instrumentation / Q000379:methods*; D012395:Rose Bengal / Q000008:administration & dosage; D013997:Time Factors; D013049:Spectrin
chemical_list: D002352:Carrier Proteins; D004573:Electrolytes; D005456:Fluorescent Dyes; D008840:Microfilament Proteins; D018696:Neuroprotective Agents; D012395:Rose Bengal; D013049:Spectrin