Effects of multiple exposures to sevoflurane anesthesia on expression of apolipoprotein E in hippocampus of neonatal rats

Abstract

Objective To evaluate the effects of multiple exposures to sevoflurane anesthesia on the expression of apolipoprotein E (ApoE) in the hippocampus of neonatal rats. Methods Twenty-four pathogen-free Sprague-Dawley rats (12 males, 12 females), aged 7 days, weighing 15-20 g, were randomly divided into 2 groups (n=12 each) using a random number table: control group (group Con) and multiple exposures to sevoflurane anesthesia group (group Sev). On postnatal day 7, 14 and 21, 2.6% sevoflurane was inhaled for 2 h in group Sev, while the mixed gas of oxygen and air was inhaled instead of sevoflurane in group Con.Morris water maze test was carried out on postnatal day 31-37 to assess cognitive function.The rats were then sacrificed, and the hippocampus was removed to determine the expression of ApoE protein in hippocampal CA1, CA3 and DG regions (by immunohistochemistry) and the expression of ApoE mRNA (by fluorescent quantitative real-time reverse transcriptase polymerase chain reaction). Results There was no significant difference between the two groups in cognitive function (P>0.05). Compared with group Con, the expression of ApoE protein in hippocampal CA1 and CA3 regions and ApoE mRNA was significantly up-regulated in group Sev (P 0.05). Conclusion Multiple exposures to sevoflurane anesthesia can up-regulate the expression of hippocampal ApoE and produce mild neurotoxicity without causing changes in cognitive function in neonatal rats. Key words: Anesthetics, inhalation; Infant, newborn; Drug toxicity; Apolipoproteins E; Hippocampus