title: Preischemic hyperglycemia leads to rapidly developing brain damage with no change in capillary patency.
abstract: The present experiments were undertaken to explore whether exaggeration of ischemic brain damage by preischemic hyperglycemia is due to lack of capillary patency in the postischemic period. Normo- and hyperglycemic rats were exposed to 10 min of forebrain ischemia. Histopathological changes were evaluated after 6 and 16-18 h of recovery by light microscopy, and capillary patency was assessed at the same time points by a double-staining technique, depicting perfused and morphologically identifiable capillaries. The results demonstrate that some neuronal damage was detectable after 6 h of recirculation which was aggravated after 16-18 h of recirculation in hyperglycemic rats. In contrast, the degree of capillary patency was similar in normo- and hyperglycemic rats. In both groups the perfusion marker, Evans blue, perfused about 95% of all capillaries when injected 10 s before decapitation. Since preischemic hyperglycemia exaggerates brain damage without cessation of capillary perfusion the primary targets of hyperglycemic brain damage may not be capillaries but neurons or glial cells.
authors.affiliation: Laboratory for Experimental Brain Research, Wallenberg Neuroscience Center, University of Lund, Sweden. lip@usask.sask.ca
authors.forename: P A
authors.initials: PA
authors.lastname: Li
authors.forename: J
authors.initials: J
authors.lastname: Vogel
authors.forename: Q P
authors.initials: QP
authors.lastname: He
authors.forename: M L
authors.initials: ML
authors.lastname: Smith
authors.forename: W
authors.initials: W
authors.lastname: Kuschinsky
authors.forename: B K
authors.initials: BK
authors.lastname: Siesjö
mesh_terms: D000818:Animals; D001925:Brain Damage, Chronic / Q000209:etiology* / Q000473:pathology; D002545:Brain Ischemia / Q000150:complications* / Q000473:pathology; D002196:Capillaries / Q000473:pathology / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D006943:Hyperglycemia / Q000150:complications*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D015424:Reperfusion; D013997:Time Factors; D014654:Vascular Patency / Q000502:physiology*