BACKGROUND:PreparationofGinkgoleafhasbeenwidelyusedtoimprovecognitivedeficitsanddementia,inparticularinAlzheimer'sdiseasepatients.However,theprecisemechanismofactionofGinkgoleafremainsunclear.OBJECTIVE:ToexploretheeffectofGinkgoBilobaextract(Egb761),Ginaton,onβ-secretaseexpressioninrathippocampalneuronalculturesfollowingchronichypoxicandhypoglycemicconditions.DESIGN,TIMEANDSETTNG:Completelybyrandomized,groupingstudy.TheexperimentwasperformedattheLaboratoryofMolecularImaging,SoutheastUniversitybetweenAugust2006andAugust2007.MATERIALS:Atotalof128Wistarratsaged24hourswereselected,andhippocampalneuronswereharvestedforprimarycultures.METHODS:Onday7,primaryhippocampalneuronalculturesweretreatedwithEgb761(0,25,50,100,150,and200μg/mL)underhypoxic/hypoglycemicorhypoglycemiccultureconditionsfor12,24,and36hours,respectively.Hippocampalneuronsculturedinprimaryculturemediumservedascontrol.MAINOUTCOMEMEASURES:Cellviabilitywasassayedusing3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide(MTT);fluorescencedetectionofβ-secretaseactivitywasperformed;WesternBlotwasusedtomeasureβ-secretaseexpression.RESULTS:Cellviabilityunderhypoxic/hypoglycemicorhypoglycemiccultureconditionswassignificantlylessthancontrolcells(P<0.05).Underhypoxic/hypoglycemicorhypoglycemiccultureconditions,treatmentwith25μg/mLEgb761didnotaltercellviability.However,>25μg/mLEgb761inducedgreatercellviability(P<0.05).Nodifferenceswereobservedbetweenhypoxic/hypoglycemicorhypoglycemiccells(P>0.05).α-secretaseactivitywasincreasedafter12hoursinhypoxic/hypoglycemicculture(P<0.01).Therewerenosignificantdifferencesbetweenthe12-,24-,or36-hourEgb761groupsandthehypoxic/hypoglycemicgroups(P>0.05).β-secretaseactivitywasgreaterafter12,24,and36hoursinhypoxic/hypoglycemiccultureconditions,comp
