中文摘要：

目的：了解年龄相关性听力损失小鼠耳蜗毛细胞的凋亡方式，探讨半胱氨酸蛋白酶（caspase）抑制剂z－VAD－FMK [z － Val － Ala － Asp （Ome）－ fluoromethylketone]防治老年性聋的效果。方法选用新生NMF308nmf／nmf小鼠14只和成年同窝NMF308nmf／nmf小鼠32只，分为新生小鼠腹腔注射组（14只）、成年小鼠腹腔注射组（14只）和成年小鼠圆窗膜注射组（18只），各组又分为治疗组（注射z－VAD －FM K ）和对照组[注射二甲基亚枫（dimethylsulfoxide ，DMSO）]，采用圆窗膜局部和腹腔注射两种方法给药，给药前后行ABR检测，用免疫荧光染色化学技术TUNEL、caspase－3和PI（碘化丙啶）染色标记耳蜗毛细胞，观察各组耳蜗毛细胞的凋亡和存活状况。结果NMF308nmf／nmf小鼠从1月龄开始发生听力减退和毛细胞功能改变，到2月龄时，caspase－3激活表达的毛细胞凋亡现象是毛细胞凋亡出现的最早表现；TUNEL阳性标记特征稍晚出现；PI标记可见毛细胞细胞核固缩和碎片出现的时间从2月龄开始；到3月龄时该种小鼠听力基本丧失，耳蜗毛细胞严重缺失；而应用z－VAD －FM K治疗后，各治疗组小鼠ABR反应阈明显好于对照组；耳蜗毛细胞凋亡数目较对照组减少，存活数明显较对照组多，尤以圆窗膜注射组明显。结论 NMF308nmf／nmf小鼠耳蜗毛细胞的死亡方式以caspase－3凋亡途径为主，应用caspase－3抑制剂z－VAD －FM K定向内耳给药，可以阻断caspase－3信号途径激活所导致的毛细胞凋亡，从而有效防治老年性聋。

英文摘要：

Objective In this study ,we investigated the apoptosis of hair cell in the cochlea of age -related hearing loss（AHL） generated by ENU mutagenesis ,and to study a pan caspase inhibitor （z-VAD -FMK） which is to protect the cochlea hair cells from hearing loss induced by age-related hearing loss（AHL） .Methods Through z-VAD-FMK intraperitoneal injection and round window membrane （RWM） drug were delivered into the Cdh23 nmf308 nmf/nmf mice 5（postnatal days 2 -32） inner ear .ResuIts The results showed that the nmf308 mice with progressive hair cell loss along a base to apex gradient with age-related hearing loss .The cochlear OHCs reduced from 5% ～10% at 1 month to 100% at 3 month in the basal region .Substantial amounts of TUNEL -positive OHCs nuclei appeared at 1 month age ,and activated caspase-3 labeling demonstrated that most OHCs appeared at 2 months age .These suggested that DNA single strand break was attributed primarily to apoptosis of cochlear le_sions ,whereas in the later stage of lesion ,the expansion led to activation of caspase-3 activity reduced with further progression of nuclear condensation in age-related hearing loss .ConcIusion The addition of a pan caspase inhibitor （z -VAD -FMK ） significantly protected the cochlea against the hair cell loss induced by apoptosis .Our study showed that aspase inhibitor ,Z-VAD-FMK appeared to play a prominent role in age-related hearing loss media_ted hair cell death loss induced by apoptosis .Our study showed that aspase inhibitor ,Z-VAD -FMK appeared to play a prominent role in age-related hearing loss mediated hair cell death .