Prolonged Exposure to Isoflurane Ameliorates Infar

Authors: Hank Chen Michael Burris Adrain Fajilan Fred Spagnoli John H Zhang Jiping Tang

Publish Date: 2011/04/20

Volume: 2, Issue: 3, Pages: 382-390

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Abstract

The neonatal hypoxiaischemia rat model referred to as the Rice–Vannucci model is extensively used to study perinatal hypoxiaischemia and child brain injury One of the major weaknesses of this model is its inconsistency of brain infarction among animals We hypothesize that the inconsistency of infarction is caused by prolonged operation time and therefore isoflurane exposure Neonatal hypoxiaischemia was induced in postnatal days 7 and 10 rat pups by unilateral right common carotid ligation followed by 25 h of hypoxia 8 oxygen The incisiontoligation ITL was defined as the amount of time from initial incision 4 min after 2 isoflurane exposure to completion of carotid ligation at which point isoflurane exposure was also terminated In the first part of the study the ITL of each group was designated to be 5 13 and 21 min In the second part of the study the ITL is designated to 4 min however continued isoflurane was used to make 5 13 and 21 min isoflurane exposure for each group Percentages of brain infarction were assessed at 48 h following surgery Motor deficits were accessed by Rotarod test Marked brain infarction was observed in the 5min ITL group and a decrease of brain infarction observed in the 13 and 21min groups P  005 In the second part of the study marked brain infarction was observed in the 5min isoflurane exposure group and a decrease of brain infarction was observed in each of the 13 and 21min isoflurane exposure groups P  005 Similar tendencies were observed in Rotarod tests than 5min ITL and 5min isoflurane groups showed more marked deficits P  005 This study demonstrated that brain infarction inconsistency of the neonatal hypoxiaischemia rat pup model is related to the operation time The observed timedependent decrease of brain infarction is correlated to the isoflurane exposure time Shorter operation and isoflurane exposure improves this model consistency of brain infarction and motor deficits

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