title: Effects of hyperglycemia on cerebral blood flow and edema formation after carotid artery occlusion in Fischer 344 rats.
abstract: This study examines whether during bilateral carotid artery occlusion in Fischer 344 rats, hyperglycemia induces cerebrovascular changes that enhance brain edema formation. Preischemic hyperglycemia was induced by intraperitoneal administration of D-glucose solution. Laser-Doppler flowmetry, indicated that after the initial decline in blood flow with carotid occlusion (36 +/- 4% of preischemic), hyperglycemic but not control rats showed a further progressive decrease to 19 +/- 2% of preischemic at 120 minutes (p < 0.001). Brain water content was significantly higher in hypercompared to normoglycemic rats after both 2 hours of permanent occlusion (3.86 +/- 0.05 vs. 3.73 +/- 0.03 g/g dry wt.; p < 0.05) and 2 hours of temporary occlusion followed by 1 hour of reperfusion (4.01 +/- 0.08 vs. 3.71 +/- 0.03 g/g dry wt.; p < 0.05). The difference in brain edema formation between normo- and hyperglycemic rats appears to primarily reflect the effects of hyperglycemia on CBF. Cerebral plasma volume (CPV) 2 hours after occlusion was also reduced in hyper-compared to normoglycemic rats (3.9 +/- 0.9 and 7.2 +/- 0.1 microliters/g; p < 0.01). Thus, hyperglycemia in a model of global ischemia induces a reduction in CPV and progressive decline in CBF. In this model, the decline in CBF is of sufficient magnitude to enhance brain injury as evidenced by edema formation.
authors.affiliation: Department of Surgery (Neurosurgery), University of Michigan, Ann Arbor, USA.
authors.forename: N
authors.initials: N
authors.lastname: Kawai
authors.forename: R F
authors.initials: RF
authors.lastname: Keep
authors.forename: A L
authors.initials: AL
authors.lastname: Betz
mesh_terms: D000818:Animals; D001157:Arterial Occlusive Diseases / Q000503:physiopathology*; D001929:Brain Edema / Q000503:physiopathology*; D002340:Carotid Artery Diseases / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D006943:Hyperglycemia / Q000503:physiopathology*; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D015427:Reperfusion Injury / Q000503:physiopathology