LASER-DOPPLER SCANNING OF LOCAL CEREBRAL BLOOD-FLOW AND RESERVE CAPACITY AND TESTING OF MOTOR AND MEMORY FUNCTIONS IN A CHRONIC 2-VESSEL OCCLUSION MODEL IN RATS

Background and Purpose-An animal model of incomplete forebrain ischemi a resembling human hemodynamic insufficiency was established. The mode l allows examination of acute and chronic changes of local cerebral bl ood flow (lCBF) and reserve capacity in correlation with behavioral pa rameters. Methods-Anesthetized male Wistar-Kyoto rats underwent bilate ral carotid occlusion (BCO), Laser-Doppler scanning of lCBF at baselin e conditions and after acetazolamide was done 30 minutes after BCO, mo tor and memory function tests were administered after 1 and 2 days, an d both investigations were repeated after 1, 2, 4, and 6 weeks. A sham -operated and a control group without any vessel manipulation served a s controls. Results- lCBF dropped within 60 minutes after surgery by 6 2% (P<0.001) in 10 animals surviving BCO (BCOsurvival) and by 69% in 5 rats that died within 9 days (BCOlethal). Acetazolamide increased ICB F to 142.33% in controls, to 136.66% in sham-operated rats (both signi ficant), and to 104.80% in BCOsurvival (not significant), and it decre ased flow by 23.1% in BCOlethal rats (P<0.001), Baseline lCBF normaliz ed within 4 weeks. Total motor function scores were significantly redu ced from 9 points preoperatively to 5.80+/-0.65 in BCOlethal and 6.68/-0.54 points in BCOlethal rats 1 day after occlusion. Memory retentio n function remained impaired after BCO, as did the acetazolamide respo nse, which correlated with motor score and was inversely related to ma ze exploration time. Conclusions-This model allows long-term follow-up of cerebral function, lCBF, and reserve capacity in a pathophysiologi cal setting similar to hemodynamic insufficiency in humans.