简介：ObjectiveToinvestigatetheearlychangeofcochlearribbonsynapsesoninnerhaircellsinresponsetoaminoglycosideototoxicity.MethodsC57BL/6Jmicereceivedintraperitonealinjectionofgentamicin(100mg/kg/day),andtheapicalcoilorganofCortiwasexaminedonthe4th,7thand10thday(n=10).Litter-mateswithoutgentamicintreatmentservedascontrols(n=10).RIBEYEonthepresynapticmembraneandAMPAreceptorsonthepostsynapticmembranewerelabeledwithCtBP2orGluR2/3respectively.Threedi-mensionreconstructionwasconductedusingthe3DSMAX8.0software.ResultsTherewerenodisruptionsofouterorinnerhaircellsinallgroups.However,thenumberofribbonsynapsesoncochlearinnerhaircellsincreasedsignificantlywithin7daysaftergentamicinexposure(P<0.01),followedbyasignificantde-creaseafter7days.ConclusionDuringtheearlystageofaminoglycosideototoxicity,increasedpopulationofcochlearribbonsynapsesmayindicateasignificantdown-regulationofsynapticfunction.

简介：ObjectiveTostudycharacteristicsofhearinglossafterexposuretomoderatenoiseexposureinC57BL/6Jmice.MethodsMaleC57BL/6Jmicewithnormalhearingatageof5-6weekswerechosenforthisstudy.Themicewererandomlyselectedtobestudiedimmediatelyafterexposure(GroupP0),or1day(GroupP1),3days(GroupP3),7days(GroupP7)or14days(P14)afterexposure.Theirbeforeexposureconditionservedasthenormalcontrol.Allmicewereexposedtoabroad-bandwhitenoiseat100dBSPLfor2hours,ABRthresholdswereusedtoestimatehearingstatusateachtimepoint.ResultsABRthresholdelevationwasseenateverytestedfrequencyatP0(P<0.01).Elevationathigh-frequencies(16kHzand32kHz)wasgreaterthanatlowerfrequencies(4kHzand8kHz,P<0.05).FromP1toP14,ABRthresholdscontinuouslyimproved,andtherewasnosignificantdifferencebetweenP14andbeforeexposure(P>0.05).ConclusionThereisafrequencyspecificresponseto100dBSPLbroad-bandwhitenoiseinC57BL/6Jmice,withthehigh-frequencybeingmoresusceptible.HearinglossinducedbymoderatenoiseexposureappearsreversibleinC57BL/6Jmice.

简介：目的探讨老年性耳蜗毛细胞损害与中药复方健耳剂两种喂药方法干预的作用。方法选择1月龄C57BL/6J小鼠22只用于本实验,其中4只小鼠每日饮用自来水直到出生后3个月作为幼龄对照组;6只小鼠每日饮用自来水直到出生后7个月作为老年性聋对照组;6只小鼠每日自动饮用中药复方健耳剂直到出生后7个月;另6只小鼠每日自动饮用同样中药至4个月后改用每日人工灌服直到出生后7个月。各组动物实验到期终止后,取耳蜗进行全耳蜗基底膜铺片,将全耳蜗内、外毛细胞计数结果输入计算机并应用耳蜗图软件进行耳蜗毛细胞密度对比分析,其中选择基底膜上重要的病变区间的毛细胞密度进行统计学分析。结果3月龄对照组小鼠耳蜗外、内毛细胞缺损仅仅出现在耳蜗底回钩端区域;7月龄对照组外、内毛细胞缺损从底回基底膜起始端扩展到距离耳蜗顶端约40%区域;7月龄中药灌服组和自动饮用组动物的内、外毛细胞缺损范围和程度相似,均显著比7月龄对照组为轻（P〈0.001）。结论中药复方健耳剂能够有效延缓C57BL/6J小鼠老年性耳蜗毛细胞损害的发生和发展,两种喂药方式所起作用相同（P〉0.05）,其药理机制可能与其改善微循环,清除活性氧,保护线粒体等作用相关。

简介：目的探讨幼年和10月龄C57BL／6J小鼠听力及初级听皮质（AI）中凋亡抑制蛋白XIAP的年龄相关变化。方法检测两组C57BL/6J小鼠听性脑干反应（ABR）；免疫组织化学法染色检测两组C57BL/6J初级听皮质神经元凋亡抑制蛋白XIAP的表达情况。结果与幼年C57BL／6J小鼠相比，10月龄C57BL/6J的ABR反应阈值更高，凋亡抑制蛋白XIAP的表达显著减少。结论随年龄增长C57BL/6J小鼠的听力减退，同时C57BL／6J小鼠大脑初级听皮质凋亡抑制蛋白表达减少，XIAP的表达水平可能与C57BL/6J小鼠听力减退有关。