Effects of exogenous glucose on brain ischemia in ovine fetuses.
We examined the effects of prolonged moderate hyperglycemia with and without an additional rapid glucose injection on ischemic brain injury in the fetus. Twenty-five ewes (117-124 d of gestation) were assigned to one of four groups: 1) glucose-infused fetuses exposed to 30 min of carotid artery occlusion followed by 48 h of reperfusion (I/R-Glu, n = 8); 2) glucose-infused plus rapid glucose injection given 100 min before 30 min of occlusion followed by 48 h of reperfusion (I/R-GluR, n = 4); 3) placebo-infused exposed to 30 min of occlusion and 48 h of reperfusion (I/R-PL, n = 8); and 4) glucose-infused sham occlusion and 48 h of sham reperfusion (control, n = 5). After baseline measurements, fetuses were infused with glucose (9-16 mg/kg/min) for 48 h before and after carotid occlusion or sham treatment. The I/R-PL group received 0.9% NaCl. Brain pathologic outcome was determined. Serial sections stained with Luxol fast blue-hematoxylin and eosin were scored for white matter, cerebral cortical, and hippocampal lesions. These areas received graded pathologic scores of 0 to 5, reflecting the amount of injury, where 0 = 0%, 1 = 1-25%, 2 = 26-50%, 3 = 51-75%, 4 = 76-95%, and 5 = 96-100% of the area damaged. Comparisons of the pathologic scores for cerebral cortex (CC), white matter (WM), and hippocampus (H) demonstrated that the I/R-GluR (CC: 4.56 +/- 0.11, WM: 4.50 +/- 0.11, H: 3.44 +/- 0.48, mean +/- SEM) had more (p < 0.05) damage than the I/R-Glu (CC: 2.46 +/- 0.47, WM: 1.97 +/- 0.37, H: 1.81 +/- 0.36) and control (CC: 1.12 +/- 0.13, WM: 0.82 +/- 0.34, H: 0.80 +/- 0.34) groups. The pathologic scores in the I/R-Glu were (p < 0.05) greater than the control, but not the I/R-PL (CC: 2.12 +/- 0.35, WM: 2.20 +/- 0.44, H: 1.59 +/- 0.41) group. We conclude that exposure to prolonged moderate hyperglycemia before ischemia and during reperfusion does not affect the extent of brain injury, but exposure to an additional acute increase in plasma glucose concentration before ischemia is extremely detrimental to the fetal brain.
Department of Pediatrics, Brown University Medical School, Providence, Rhode Island 02905, USA.
Katherine H
KH
Petersson
Halit
H
Pinar
Edward G
EG
Stopa
Grazyna B
GB
Sadowska
R Choudary
RC
Hanumara
Barbara S
BS
Stonestreet
D000818:Animals; D001786:Blood Glucose; D001921:Brain / Q000473:pathology; D002545:Brain Ischemia / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D002245:Carbon Dioxide / Q000097:blood; D005260:Female; D005315:Fetal Diseases / Q000473:pathology / Q000503:physiopathology*; D005947:Glucose / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D006943:Hyperglycemia / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D011247:Pregnancy; D015427:Reperfusion Injury / Q000150:complications / Q000473:pathology / Q000503:physiopathology; D012756:Sheep
D001786:Blood Glucose; D002245:Carbon Dioxide; D005947:Glucose