热应激小鼠脑电图表现及脑组织的电镜观察分析

(24343738.54042,60min,60%),3437,,;,,,4242,,40,42,;;;;,,R363.123ElectronmicroscopicstudyofbraintissueandEEGofmouseafteracuteheatstressYangFen,WanQi,WuSongdi.DepartmentofNeurology,XijingHospital,FourthMilitaryMedicalUniversi2ty,Xian710032,ChinaAbstractObjectiveTostudythechangesinthecentralnervoussysteminadultmiceaftervariousdegreesofacuteheatstress.MethodsAdultmiceplacedininsulatedcageswereexposedto24,34,37,38.5,40or42for60minrespectivelywithaconstanthumidityof60%.Thebehaviorresponsewascarefullymonitored.Rectaltemperaturewasmeasuredbeforetheexposureandaftertheexposure.Electroencephagramsweretaken.Thenthehippocampalneuronsoftheseanimalswereexaminedwithtransmissionelectronmicroscope.ResultsHeatstressat34for60minonlyraisedtherectaltemperature,andheatstressabove37for60minnotonlyraisedrectaltemperature,butalsoinducedwaterlossandirritabilityandattempttoescape.AbnormalEEGwithincreasedamplitudeandretardedrhythmcouldbeobserved.However,whenmicewereexposedto24and34suchbehaviordidnotappear.Afterexposureto42,EEGfrequencyincreasedandpathologicalchangesinhippocampusneuronswerefound.Themainultrastructuralchangesincludeddegenerationofhippocampalneurons,expansionofspacearoundcapillary,decreaseinnumberofsynapticvesicle,anddecompositionofsynapse.ConclusionMicewereverysensitivetoheatstress.Anincreaseincoretemperaturecouldinducebehavioralthermoregulation.EEGandelectronmicroscopicstudyrevealedchangesinthecentralnervoussystemafterheatstress.Followingexposuretohighenviron2mentaltemperatureunder40,acutedysfunctionofbrainwasreversible.At42,damagetothebraintissueoccurred,andmostmicediedofheatstroke.Keywordsheatstress;behavior;electroencephalography;electronmicroscope;hippocampus,electron,scanningtransmission,,,,,,11.136,6,,6,24343738.540426,615:(221),40%50%,,9:0020:00,(),24343738.54042,60%,60min2cm,1.2,1.3,,,,,,,3cm/s,50V/5mm1.4,1%,,,10ml,4%40ml:,:710032():,:029284775921,E2mail:[e-mail]56120062312MedJChinPLAVol31No2February2006,,1mm3,,22.1363834,,,39,37,,60min39,,,,,,,,,42,42,,2.22410Hz,,,,,34Hz343738.540,42,,2.324,,,,,;,;343738.540,,42,,,,,,,,;,;,3,,,,34,,37,,,,,[1,2],[3],,34HzSinha[4]38.542,,,343738.540,,,,42,,,,,3935,S100[5],[6],,,1NagashimaK,NakaiS,KonishiMetal.Increasedheat2escape/cold2seekingbehaviorfollowinghypertonicsalineinjectioninrats.AmJPhysiolRegulIntegrCompPhysiol,2001,280(4):10312KonishiM,NagashimaK,KanosueK.Systemicsaltloadingdecreasesbodytemperatureandincreasesheat2escape/cold2seekingbehaviourviathecentralAT1andV1receptorsinrats.JPhysiol,2002,545(1):2893HarikaiN,TomoganeKJ,MiyamotoMetal.Dynamicresponsestoacuteheatstressbetween34and38.5,andcharacteristicsofheatstressresponseinmice.BiolPharmBull,2003,26(5):7014SinhaPK.Electro2encephalogramdisturbancesindifferentsleep2wakestatesfollowingexposuretohighenvironmentalheat.MedBiolEngComput,2004,42(3):2825WatsonP,ShirveffsSM,MaughanRJ.Blood2brainbarrierintegritymaybethreatenedbyexerciseinawarmenvironment.AmJPhysiolRegulIntegvCompPhysiol,2005,288(6):16896SharmaHS,HoopesPJ.Hyperthermiainducedpathophysiologyofthecentralnervoussystem.IntJHyperthermia,2003,19(3):325(20052082222005211220)()66120062312MedJChinPLAVol31No2February2006