The Effects Of Etomidate Or Propofol On Cognitive Function And Hippocampus In Newborn Rats

Objective:To investigate the effects of etomidate or propofol on earlyspatial cognitive, exploring,learning and memory abilities and neuronsform,caspase-3,GABA of hippocampus in newborn rats. Methods:Fifty sevenSD rats with an age from17to18days，which were screened by Y-maze, wererandomly divided into group C(control group, normal saline(10ml/kg) wasintraperitoneal injected singly),group E(Etomidate group,5mg/kg ofetomidate),group P(Propofol group,50mg/kg of propofol)(n=19). After3hoursof injected normal saline and anesthesia awake,the tests of cognitive fuctionwere perfomed in Open Field Test,Hole Board Test and Y-maze Test(n=10).Application of HE staining method to observe the morphology of hippocampusneuron tissue and application of immunohistochemistry(IHC) method todetection the expression of aspartic acid specificity cysteine protease (caspase-3)in hippocampal neurons(n=3). The other6rats were killed to test the GABA content in hippocampal tissue at3hours of postanesthesia.Results:(1) Beforeanesthesia, the weight of three groups of rats between comparative differenceshad no statistical significance (P>0.05);there were no statistical significancebetween three groups of rats of learning and memory ability.(2)In the OpenField Test, there was no significant difference between group C and group Eand group P about the retention time in central check and the locomotion(P＞0.05).(3)In the Hole Board Test,the rats of groups E and P about the times ofrats stretch into the hole were significant different comparing with group C(P＜0.05).(4)In the Y-maze Test,compared with group C,the group E in the rightnumber and total reaction time were no significant difference (P＞0.05).Theright number of group P were abviously decreased(P＜0.01) as compared withgroup C,and there also have significant difference between group E(P＜0.05).Inaddition,the total reation time between group P and group C was significantdifference(P＜0.05).(5)In HE stainin, Three groups of hippocampus CA1areawas found no obvious difference between the neurons number and themorphology of vertebral body, CA1area normal nerve cells in the form,arrangement of the basic rules, neuron density uniform, no obvious vertebralbody cell degeneration and necrosis.(6)In IHC, the expression of caspase-3between groups C,E and P,there were no significant difference(P＞0.05).(7) Thecontent of GABA: Group C:39.08±10.56mg/100g；Group E:47.88±10.86mg/100g；Group P：73.14±11.79mg/100g。Compared with group C, there was no significant increase in group E. Compared with group C and group E, therewas a significant increase of GABA content in group P (P＜0.01).Conclusion:(1)Single intraperitoneal injection of5mg/kg etomidate and50mg/kg propofol onearly newborn rat all affect the cognitive functions, etomidate in ability ofexploring, propofol in two aspects of ability of explore,learning and memory.(2)Etomidate and propofol on hippocampus neurons form, the expression ofCaspase3had no significant effect.(3) Propofol may affect the early cognitivefunction of the newborn rat by increasing the synthesis and secretion ofgamma-aminobutyric acid.