简介：NuclearfactorkappaB(NF-κB)isoneofthebest-characterizedtranscriptionfactorsplayingimportantrolesinmanycellularresponsestoalargevarietyofstimuli,includinginflammatorycytokines,phorbolesters,growthfactors,andbacterialandviralproducts.TheaimofthisstudyistodemonstrateNF-κBexpressioninthemousecochleaanditsenhancementinresponsetolipopolysaccharides(LPS)andkanamycin(KA)treatment.MethodsKAtreatmentconsistedofsubcutaneousKAinjectionsat700mg/kgtwiceadaywithaneight-hourintervalbetweenthetwoinjectionsfor3or7days.ForanimalsintheLPStreatmentgroup,asingledoseof0.3mgLPSdissolvedin0.2mlsterilesalinewereinjectedintobothbullaethroughthetympanicmembraneandkepttherefor3hours.Animalsinthecontrolgroupreceivedsubcutaneoussalineinjectionfor7days.Followingimmmunohistochemichalprocessingwithrabbitpolyclonalanti-NF-κBp65antibodies,cryosectionsofthecochleawereexaminedforexpressionofNF-κBp65invariousstructuresinthecochlea.ResultsNF-κBp65expression,identifiedbypresenceofbrownreactionproductscharacteristicofDABimmunohistochemistry,wasvisibleinthespiralligament,spiralprominence,tectorialmembrane(TM),spiralganglionandnervefibers.RelativelyweakNF-κBp65expressionwasalsovisualizedintheorganofCorti.WithintheorganofCorti,theinnerhaircells(IHC),outerhaircells(OHC),innerpillarcells(IP),outerpillarcells(OP),Deiter'scells(DC),andBoettcher'scellsexhibitedstrongerstainingthantheinnersulcuscells,Hensen'scells(HC)andClaudius'cells.NoNF-κBp65expressionwasseeninthenucleusoftheIHCandOHC.NF-κBp65expressionwasincreasedinanimalsexposedtoLPSorKA,demonstratingsignificantdifferencesinthestainingbetweencontrolanimalsandLPS/KA-treatedanimals.NF-κBp65expressionwasnotsignificantlydifferentbetweenLPStreatedandKAtreatedanimalsorbetween3and7daysinKA-treatedanimals.Conclusio

简介：Thepurposeofthepresentstudywastodetermineprotectivieeffectsofbasicfibroblastgrowthfactor(bFGF)oncochlearneuronsandhaircellsinvitroandinvivo.InexperimentI,culturedspiralganglionneurons(SGNs)preparedfromP3micewereexposedto20mMglutamatefor2hoursbeforetheculturemediumwasreplacedwithfreshmediumcontaining0,25,50,and100ng/mlbFGF,respectively.Fourteendayslater,allcultureswerefixedwith4%paraformaldehyde,andstainedwith1%toluidineblue.ThenumberofsurvivingSGNswerecountedandthelengthofSGNsneuritesweremeasured.Exposureto20mMglutamatefor24hoursresultedinaninhibitiononneuriteoutgrowthofSGNsandelevatedcelldeath.TreatmentofthecultureswithbFGFledtopromotionofneuriteoutgrowthandelevatednumberofsurvivingSGNs.EffectsofbFGFweredosedependentwiththehighestpotencyat100ng/ml.InexperimentⅡ,invivostudieswerecarriedoutwithguineapigsinwhichbFGForartificialperilymphwasperfusedintothecochleatoassesspossibleprotectiveeffectsofbFGFoncochlearhaircellsandcompoundactionpotentials(CAP).TheCAPsweremeasuredbefore,immediatlyand48hoursafterexposuretonoise.SignificantdifferencesinCAPwereobserved(p＜0.05)amongthebFGFperfusedgroup,controlgroup(t=3.896)andartificialperilymphperfusedgroup(t=2.520)at48hoursafternoiseexposure,CochleaewereremovedandhaircellLosswasanalyzedinsurfacepreparationspreparedfromallexperimentalanimals.Acoustictraumacausedlossof651and687innerhaircellsinthecontrolandartificialperilymphperfusedgroup,respectively.Insharpcontrast,only31innerhaircellswerelostinthebFGFperfusedears.Similarly,moreouterhaircellsdiedinthecontrolandperilymphperfuesedgroup(41830and41968,respectively)thaninthegrouptreatedwithbFGF(34258).OurresultsdemonstratethatbFGFprotectedSGNsagainstglutmateneurotoxicityinvitro.Inaddition,treatmentwithbFGFalso

简介：Thedevelopmentandplasticityofcentralauditorysystemcanbeinfluencedbythechangeofperipheralneuronalactivity.However,themolecularmechanismparticipatingintheprocessremainselusive.Brain-derivedneurotrophicfactor(BDNF)bindingwithitsfunctionalreceptortropomyosinreceptorkinaseB(TrkB)hasmultipleeffectsonneurons.Hereweusedaratmodelofauditorydeprivationbybilateralcochlearablation,toinvestigatethechangesinexpressionofBDNFandTrkBintheauditorycortexafterauditorydeprivationthatoccurredduringthecriticalperiodforthedevelopmentofcentralauditorysystem.Reversetranscription-quantitativepolymerasechainreaction(RTqPCR)andimmunohistochemistrymethodswereadoptedtodetectthemRNAandproteinexpressionlevelsofBDNFandTrkBintheauditorycortexat2,4,6and8weeksaftersurgery,respectively.ThechangeintheexpressionofBDNFandTrkBmRNAsandproteinsfollowedsimilartrend.Inthebilateralcochlearablationgroups,theBDNF-TrkBexpressionlevelinitiallydecreasedat2weeksbutincreasedat4weeksfollowedbythereductionat6and8weeksaftercochlearremoval,ascomparedtotheage-matchedshamcontrolgroups.Inconclusion,theBDNF-TrkBsignalingisinvolvedintheplasticityofauditorycortexinanactivity-dependentmanner.

简介：Olderadultsoftenfinditdifficulttoperceivespeech,especiallyinnoisyconditions.Thoughhearingaidisoneoftherehabilitativedevicesavailabletoolderadultstoalleviatehearingloss,someofthemmayexperienceannoyancethroughhearingaidandhencerejectit.maybeduetocircuitrynoiseand/orbackgroundnoise.Acceptablenoiselevelisadirectbehaviouralmeasuretoestimatetheextentofhowmuchapersonisabletoputupwithnoisewhilesimultaneouslylisteningtospeech.Acceptablenoiselevelisacentralauditorymeasureanditisnotinfluencedbyage.gender,presentationlevelorspeaker.Usingthismeasure,wecanquantifytheannoyancelevelexperiencedbyanindividual.Thisinformationisofutmostimportanceandcautionshouldbepaidbeforesettingtheparametersinhearingaid,especiallyforthosewhoareunabletoacceptnoise.Inthisreviewarticle,anattempthasbeenmadetodocumenthowtooptimizethehearingaidprogrambysettingparameterssuchasnoisereductioncircuit,microphonesensitivityandgain.Theseadjustmentsofparametersmighthelptoreducerejectionrateofhearingaids,especiallyinthoseindividualswhoareannoyedbybackgroundnoise.