Postischemic hyperglycemia is not protective to the neonatal rat brain

Abstract

Brain glucose concentration during and after hypoxia-ischemia may be one of the variables affecting outcome of asphyxial insults. Glucose given before global ischemic forebrain injury to adult rats increases morphologic brain damage, and postischemic insulin administration reduces selective neuronal necrosis and cortical infarction. Because glucose infusions are routinely used in the clinical management of perinatal asphyxia, we evaluated the role of glucose administration after ischemic neuronal damage to neonatal rat brain. Sprague-Dawley rat pups (postnatal d 7) were subjected to left common carotid artery ligation followed by 2.5 h of 8% oxygen (Levine procedure). The experimental group was subdivided so that pups received either systemic injections of glucose or saline immediately after the hypoxic insult. Animals were killed on postnatal d 12 and brain areas of ipsi- and contralateral cortex and caudate were calculated from camera lucida tracings. There was no significant difference in size of brain infarction between postischemic glucose-treated and post-ischemic saline-treated pups. However, hypoxic-ischemic brains did show more severe neuronal damage when hyperglycemia was induced after asphyxia. Because post-ischemic hyperglycemia does not attenuate and may exacerbate injury, we recommend careful monitoring of blood glucose so that hyperglycemia does not occur during resuscitation of asphyxiated infants.