Effect of propofol anesthesia on expression of β-secretase 1 and content of anyloid beta protein 1-42 in neonatal rat hippocampus

Abstract

Objective To investigate the effect of propofol anesthesia on the expression of β-secretase 1 (BACE1) and content of anyloid beta protein 1-42 (Aβ1-42) in the neonatal rat hippocampus.Methods Ninety Sprague-Dawley rats,aged 7 days,weighing 12-16 g,were randomly divided into 3 groups ( n =30 each):control group (group C),single dose of propofol anesthesia group (group SP),and repeated doses of propofol anesthesia group (group RP).Group C received intraperitoneal normal saline 7.5 ml/kg once a day for 7 consecutive days.Group SP received normal saline 7.5 ml/kg once a day for 6 consecutive days and propofol 75 mg/kg on 7th day.Group RP received propofol 75 mg/kg once a day for 7 consecutive days.Six rats in each group were chosen at 15 min after the end of injection on 7th day and blood samples were taken from the left ventricle for determination of the blood glucose level and for blood gas analysis.Eight animals in each group were sacrificed on 1st,3rd and 7th day after the end of injection on 7th day to determine the expression of BACE1 (using Western blot) and content of Aβ1-42 in the hippocampus (by ELISA).Results Compared with groups C and SP,the expression of BACE1 was up-regulated and the content of Aβ1-42 was significantly increased at each time point in group RP ( P ＜ 0.01 ).There was no significant difference in the expression of BACE1 and content of Aβ1-42 at each time point between groups C and SP ( P ＞ 0.05).Conclusion Repeated doses of propofol up-regulate the expression of BACE1 and increase the content of Aβ1-42 in neonatal rat hippocampus,which may be one of the mechanisms by which propofol leads to long-term cognitive dysfunction.Single dose of propofol does not have the effect. Key words: Propofol; Hippocampus; Amyloid beta-protein; Infant, newborn; β-secretase 1