Effect Of Propofol Anesthesia On Cognitive Function And Content Of Amyloid Beta Protein1-42of Hippocampus In Neonatal Rat

Objective: To investigate the effect of propofol anesthesia on cognitivefunction and content of amyloid beta protein1-42(Aβ_1-42) ofhippocampus in the neonatal rat.Methods: One hundred and fourteen Sprague-Dawley rats, aged7days,weighing12-16g, were randomly divided into3groups （n=38each）:control group （group C）, single dose of propofol anesthesia group （groupSP）, and repeated doses of propofol anesthesia group （group RP）. Group Creceived intraperitoneal normal saline7.5ml/kg once a day for7consecutive days. Group SP received normal saline7.5ml/kg once a dayfor6consecutive days and propofol75mg/kg on7th day. Group RPreceived propofol75mg/kg once a day for7consecutive days. Six rats ineach group were chosen at15min after the end of injection on7th day andblood samples were taken from the left ventricle for determination of theblood glucose level and blood gas analysis. Eight rats in each group weresacrificed on1st,3rd and7th day after the end of injection to determine the expression of BACE1by Western blot and content of Aβ_1-42in thehippocampus by ELISA. The other rats were subjected to Morris watermaze to access cognitive function on14th day after the end of injection anddecapitated immediately after the tests. Then using the above method todetect the expression of BACE1and content of Aβ_1-42in the hippocampus.Results:1. The results of blood gas analysis and blood glucose of each groupwere in normol range（P>0.05）.2. Morris water maze results showed that the escape latency wereobviously prolonged and the space exploration time were shorted in groupRP compared with that of group C and SP （P <0.05）. But there were nosignificant difference between group C and SP （P>0.05）.3. Western bolt results revealed that the expression of BACE1wassignificantly up-regulated on1st,3rd,7th and14th day after the end ofinjection in group RP compared with that of group C and SP （P<0.01）.However, There were no significant difference between group C and SP（P>0.05）4. ELISA results showed that the content of Aβ_1-42was significantlyincreased on1st,3rd,7th and14th day after the end of injection in groupRP compared with that of group C and SP （P<0.01）. But there were nosignificant differences between group C and SP （P>0.05）. Conclusion:1. Repeated doses of propofol can significantly up-regulate theexpression of BACE1and increase the content of Aβ_1-42in hippocampus ofneonatal rat.2. Propofol repeated anesthesia induces long-term cognitivedysfunction which may be associated with the up-regulated expression ofBACE1and increased content of Aβ_1-42in hippocampus of neonatal rat.