快速老化小鼠的听功能和耳蜗螺旋神经元的增龄性变化

目的探讨快速老化小鼠听觉功能和耳蜗螺旋神经元的增龄性变化。方法选取1、3、5、7、9月龄的快速老化小鼠亚系1( Senescence accelerated mouse/prone 1, SAMP 1)作为实验组，而同龄抗快速老化小鼠亚系1(Senescence accelerated mouse/resistance 1, SAMR 1) 作为SAMP 1的正常对照组。分别观察其8kHz短纯音听觉脑干反应阈值、耳蜗螺旋神经节细胞透射电镜形态学、末端脱氧核苷酸转移酶介导的dUTP原位切口末端标记［terminal deoxynucleotidyl transferase(TdT) dUTP nick end labeling］ TUNEL免疫组化染色等方面的增龄性变化。结果① 听功能检测。第7、9个月龄SAMP 1小鼠跟同龄SAMR 1小鼠比较听觉脑干反应阈值差异有统计学意义；② 耳蜗螺旋神经节细胞形态学检测。第7、9个月龄SAMP 1小鼠可见螺旋神经元凋亡，而同龄SAMR 1小鼠罕见螺旋神经元凋亡；③ 耳蜗中轴位切片TUNEL染色。第7个月龄SAMR 1小鼠SGN细胞核基本上不着色［TUNEL染色阳性率为（2.27±2.43）%］，第7个月龄SAMP 1小鼠部分SGN胞核着色［染色阳性率为（11.36±4.96）%］，两者的染色阳性率差异有统计学意义。结论SAMP 1小鼠随月龄增长耳蜗螺旋神经元凋亡、听功能减退，7月龄SAMP 1小鼠即出现明显的听功能老化特征，可作为老年聋动物模型用于耳聋的相关研究。     

快速老化痴呆小鼠听功能及耳蜗螺旋神经节细胞MeCP2增龄性变化

目的探讨快速老化痴呆小鼠听觉功能、耳蜗螺旋神经节细胞（spiral ganglion cell,SGC）甲基化CpG结合蛋白2（methyl-CpG-binding protein 2,MeCP2）表达的增龄性变化。方法检测5、7月龄快速老化小鼠亚系8（senescence accelerated dementia mouse/prone,SAMP8）和同龄抗快速老化小鼠亚系1（senescenceaccelerated mouse/resistance 1,SAMR 1）8 kHz短纯音听觉脑干反应阈值以及SGC的MeCP2免疫组化染色等方面的增龄性变化。结果①第5、7月龄SAMP8小鼠双耳听觉脑干反应阈值较同龄SAMR1小鼠明显提高（5月龄左侧t=5.84,P〈0.05,右侧t=3.31,P〈0.05;7月龄左侧t=5.11,P〈0.05,右侧t=5.11,P〈0.05）;②MeCP2蛋白在不同月龄快速老化小鼠耳蜗组织中均有表达,第5、7月龄SAMP8小鼠SGC中的MeCP2蛋白较同龄SAMR1小鼠明显降低（5月龄t=2.80,P〈0.05;7月龄t=4.64,P〈0.05）。结论 SGC中MeCP2蛋白的表达水平随着快速老化小鼠听觉功能增龄性减退而降低,说明MeCP2蛋白可能与听觉形成有关。     

RAGE和NF-kB及p21在小鼠螺旋神经节细胞的表达研究

目的：通过研究晚期糖基化终产物受体（RAGE）、核转录因子NF-xB、p21在幼、老年C57BL／6j小鼠螺旋神经节细胞（SGC）的表达，探讨老年性聋的发病机制。方法：将C57BL／6j小鼠分为2月龄、10月龄组各25只，分别行组织学切片观察耳蜗SGC形态结构，免疫组织化学检测RAGE、NF_xB、p21在SGC中的表达，利用IPP6图像分析软件计算平均光密度值，值越大，表达量越多。结果：①10月龄小鼠SGC数目明显比2月龄少，分别为（20±6）个和（39±5）个，差异有统计学意义（P〈0．01）；②RAGE在2月龄和10月龄小鼠耳蜗SGC平均光密度值分别为0．179±0．025和0．308±0．050；NF-”B在2月龄和lO月龄小鼠耳蜗SGC平均光密度值分别为0．181±0．045和0．335±0．120；p21在2月龄和10月龄小鼠耳蜗SGC平均光密度值分别为0．160±0．023和0．365±0．031，两组分别比较，差异均有统计学意义（P〈O．05）。结论：RAGE、NF-kB、p21在SGC中有表达且随年龄增大表达增多，推测RAGE、NF-xB、p21可能参与老年性聋的发病过程。     

PDCD5和caspase3在不同年龄段C57BL/6J小鼠耳蜗中的表达

目的 检测程序化细胞死亡分子5（programmed cell death 5,PDCD5）和半胱氨酸天冬氨酸蛋白酶3（caspase 3）在不同年龄段C57BL/6J小鼠耳蜗中的表达,初步探讨其在年龄相关性听力下降发生、发展中的作用。方法 选择3、6、9及12月龄段C57BL/6J小鼠各15只,即按月龄分为四组。检测各组小鼠双侧短声( click)及短纯音(6、8 kHz)听性脑干反应(ABR)阈值。采用免疫组化和蛋白质印迹杂交(Westem blotting)检测各月龄段小鼠耳蜗PDCD5和Caspase3蛋白的表达,实时荧光定量PCR( real-time PCR)检测各月龄段小鼠耳蜗PDCD5和caspase 3基因mRNA的表达。结果 随着年龄的增长,C57BL/6J小鼠各频率ABR阈值逐渐提高,耳蜗PDCD5和Caspase3蛋白的表达亦逐渐增强。3月龄和6月龄小鼠耳蜗毛细胞和血管纹细胞仅出现少量PDCD5和Caspase3蛋白表达,9月龄时表达有明显增加,至12月龄时表达最强,各月龄组间比较,差异具有统计学意义(P值均＜0.05)。Real-time PCR检测显示PDCD5和caspase3基因mRNA随着年龄的增长表达逐渐增强,与其蛋白变化趋势相一致。结论 C57 BL/6J小鼠耳蜗PDCD5和caspase3随着年龄的增长表达增强,与耳蜗的老化密切相关,可能是老年性聋发病机制中的一个重要因素。     

不同月龄BALB/c小鼠耳蜗miR-96表达与ABR阈值及耳蜗形态的关系

目的　研究不同月龄BALB/c小鼠ABR阈值、耳蜗形态学改变及miR-96的表达,明确miR-96对老年性聋小鼠听力的调节作用。方法　通过听性脑干反应测试、荧光染色、扫描电镜,观察3、6、12、18月龄BALB/c小鼠8 kHz听反应阈值及耳蜗形态学改变。实时定量PCR定量检测miR-96在各月龄BALB/c小鼠耳蜗内的表达。SPSS13.0统计软件进行 统计分析。结果　3、6、12月龄组小鼠8 kHz听反应阈值分别为（18.5±8.3）、（45.8±7.8）、（85.6±15.6）dB SPL,18月龄组120 dB SPL刺激声基本测不出听觉反应。荧光染色及扫描电镜发现,自6月龄起毛细胞出现显著缺失,静纤毛出现不同程度缺失、倒伏、融合、变短和转位等改变,并随月龄增大病变逐渐加重。miR-96在3、6、12、18月龄BALB/c小鼠耳蜗中的相对表达量（2-△CT）分别为0.0225±0.0073、0.0162±0.0048、0.0116±0.0048和0.0050±0.0014,与3月龄小鼠相比,差异有统计学意义（P <0.05）。结论　BALB/c小鼠听力损失、耳蜗毛细胞缺失及纤毛损害随月龄增长而逐渐加重,小鼠耳蜗中miR-96表达随月龄增加而减少,提示miR-96可能在老年性聋的发病机制中起重要用。     

年龄相关性听力减退小鼠耳蜗核iTRAQ定量蛋白质组学研究

目的研究年龄相关性听力减退小鼠耳蜗核蛋白质组学随增龄产生的差异, 探讨低级听觉中枢在老年性耳聋发病机理中的作用。方法运用脑干电反应测听(ABR)检测2月龄及12月龄C57BL/6J小鼠的听阈,结合同位素标记的相对与绝对定量（iTRAQ）和Q Exactive质谱及生物信息学等多重技术分析两组之间耳蜗核差异蛋白。结果两组中总共鉴定到5 919个蛋白质,39 269个唯一肽段。符合表达差异倍数大于1.2倍且P＜0.05筛选标准的差异表达蛋白质70个。其中上调差异表达蛋白44个,下调差异表达蛋白26个。结论 iTRAQ定量蛋白质组学技术可有效地运用于组织蛋白鉴定和相对与绝对定量;采用该技术获得了年龄相关性听力减退小鼠耳蜗核蛋白质组差异表达图谱; 深层次研究这些蛋白的分子机制将有助于阐明老年性耳聋尤其是中枢性老年性耳聋的发病机理及发现潜在的标志物,为老年性耳聋的诊断和治疗提供新的分子靶位。     

杂色和白色豚鼠听反应阈及耳蜗血管纹细胞增殖活？…

目的 研究染色和白色成年豚鼠正常听反应阈及耳蜗血管纹细胞增殖活性的差异。方法 用听觉诱发电位仪分别测定杂色和白色豚鼠４０Ｈｚ听觉相关电位（４０Ｈｚ ＡＦＲＰ）及听性脑干反应（ＡＢＲ）阈值，用免疫组化法检测两种豚鼠耳蜗血管纹增殖细胞核抗原（ＰＣＮＡ）表达的差异。结果 杂色和白色豚鼠耳蜗血管纹中间细胞ＰＣＮＡ染色均呈阳性，但前者ＰＣＮＡ的表达显著强于后者；两种豚鼠的听反应阈值无显著性差异。结论 正常染     

DR5在GJB2基因条件敲除小鼠耳蜗表达分布及年龄相关性变化

目的研究GJB2基因条件敲除（cCx26Pax2Cre）小鼠耳蜗DR5表达情况，探讨GJB2基因突变导致耳聋的机制。方法 cCx26Pax2Cre小鼠为实验组，BALB/C小鼠为对照组，分别取P8、P12和P21时小鼠耳蜗行冰冻切片，利用荧光标记免疫组织化学方法和激光共聚焦显微镜技术观察死亡受体5（death receptor，DR5）蛋白在耳蜗的表达情况，用Image Pro Plus 6.0计算平均光密度值，SPSS 18.0进行统计分析。结果 P8时DR5主要表达在柯蒂氏器外侧的支持细胞、耳蜗外侧壁Ⅱ型纤维细胞、盖膜，随着日龄的增加，表达逐渐向内侧延伸到内侧支持细胞，P12和P21时还出现了螺旋缘、毛细胞、螺旋神经节细胞、螺旋凸DR5表达阳性，而且表达强度随日龄增加而逐渐变强。在野生小鼠DR5也有表达但较弱。与野生型小鼠相比， cCx26Pax2Cre小鼠耳蜗蜗轴螺旋管内神经纤维DR5表达的光密度值明显增大，经统计学分析两者具有显著性差异（P＆lt;0.05）。结论 cCx26Pax2Cre小鼠缝隙连接功能异常，可能导致耳蜗细胞出现葡萄糖短缺，导致三磷酸腺苷（adenosine-triphosphate， ATP）不足，引起DR5的表达上调，直接激活凋亡的死亡受体途径，或间接激活线粒体通路使凋亡信号进一步放大，导致耳蜗细胞凋亡的发生，最终引起cCx26Pax2Cre小鼠听力下降。     

晚期糖基化终产物受体在小鼠耳蜗中表达的初步探讨

目的通过研究晚期糖基化终产物受体(RAGE)在小鼠耳蜗中的表达,初步探讨RAGE与老年性聋关系。方法将C57BL/6J小鼠分为2月龄、10月龄组,分别行ABR阈值检测,组织学切片观察耳蜗形态结构,免疫组化和realtime PCR检测RAGE在耳蜗中的定位和定量表达,半定量RT-PCR检测其配体S100B在耳蜗中的表达情况。结果 :(1)10月龄小鼠较2月龄ABR阈值明显提高;(2)RAGE主要在两组小鼠耳蜗的螺旋神经节细胞,内外毛细胞和血管纹中表达,10月龄C57BL/6J小鼠耳蜗中RAGE平均光密度值比2月龄小鼠大,两组间差异有统计学意义;(3)2月龄组耳蜗中RAGE相对表达量为1±0.15,10月龄组小鼠耳蜗中RAGE相对表达量为2.0816±0.117,两组间差异有统计学意义;(4)配体S100B在10月龄小鼠耳蜗中表达增高。结论 RAGE在C57BL/6J小鼠耳蜗中有表达且随年龄增大表达增强,可能与配体S100B相互作用导致听力下降,提示RAGE可能与老年性聋的发病机制有关。     

顺铂诱导氧化应激引起耳蜗血管纹周细胞线粒体途径的细胞凋亡北大核心CSCD

目的:探讨顺铂是否通过诱导氧化应激水平升高引起耳蜗血管纹毛细血管周细胞线粒体途径的细胞凋亡。方法:将20只6~8周的雄性C57BL/6J小鼠分为对照组和顺铂组;同时原代培养小鼠耳蜗血管纹周细胞并鉴定，分为对照组、顺铂组和N-乙酰半胱氨酸（N-acetylcysteine，NAC）+顺铂组。听性脑干反应（ABR）检测小鼠听力变化，苏木精-伊红（HE）染色观察小鼠耳蜗血管纹形态学变化，总超氧化物歧化酶（superoxide dismutase，SOD）活性检测试剂盒（WST-1法）和硫代巴比妥酸（thiobarbituric acid，TBA）法分别检测SOD活性和丙二醛（malondialdehyde，MDA）含量，DCFH-DA荧光探针检测周细胞上活性氧的含量，Hoechst 33342和流式细胞术检测周细胞的凋亡率，免疫荧光技术检测耳蜗血管纹上周细胞的凋亡相关蛋白分布表达，免疫组化和蛋白免疫印迹法（WB）检测凋亡相关蛋白、线粒体相关蛋白的表达，Mito SOX TM-red和JC-1检测周细胞线粒体功能，伊文思蓝染色观察血迷路屏障（blood labyrinth barrier，BLB）的通透性。采用SPSS 18.0软件进行统计分析。 结果:与对照组相比，顺铂组可升高小鼠听力阈值和Ⅰ波潜伏期（ t值为4.72和12.25， P值均<0.05），升高耳蜗和周细胞内氧化应激水平（ t=38.34， P<0.01），使耳蜗血管纹结构紊乱皱缩，BLB通透性增加［伊文思蓝渗漏（1.08±0.42）AU比（0.55±0.23）AU， t=4.64， P<0.05］，差异均有统计学意义。顺铂组小鼠耳蜗血管纹细胞凋亡蛋白c-Caspase-3和Bax的表达增加（ t值为5.01和6.33， P值均<0.01），且顺铂可使原代培养的周细胞凋亡并上调c-Caspase-3、Bax的表达（ P值均<0.05），NAC+顺铂组可逆转顺铂诱导的周细胞凋亡（ P<0.05）。顺铂使周细胞线粒体功能损伤，诱导线粒体向胞浆释放凋亡诱导因子（apoptosis-inducing factor，AIF）和细胞色素C（cytochrome-c，Cyt-c），NAC+顺铂组可逆转顺铂诱导的线粒体损伤（ P值均<0.05）。 结论:顺铂可升高耳蜗内氧化应激水平引起C57BL/6J小鼠耳蜗血管纹周细胞线粒体途径凋亡，从而提高BLB的通透性，造成听力损失。     

Ultrastructural and physiological defects in the cochlea of the Mpv17 mouse strain. A comparison between young and old adult animals

Ultrastructural investigations were performed in young (approximately 2 months) and old (7 months) Mpv17-negative and wild-type mice. The onset, the severity and the pattern of the degeneration significantly differed between both mice strains. In the wild-type mouse strain the degenerative changes of the cochlear structures were similar to the aging pattern described for other species. In contrast, the Mpv17 mutants showed degenerative changes of the cochlear structures already at the age of 2 months. The degenerative changes were patchy arranged throughout the entire length of the cochlea and involved the organ of Corti as well as the stria vascularis epithelia with alterations of the basement membrane of the capillaries. The severe sensorineural hearing loss and degenerative changes of the cochlear structures indicate that cochlear structures, especially the outer hair cells and the intermediate cells of the stria vascularis, are vulnerable to the missing Mpv17 gene product.     

Age-related changes in the murine cochlear lateral wall

Cochleas from C57BL/6 mice were investigated electrophysiologically and histochemically to evaluate the pathology of presbycusis. The average auditory brainstem response thresholds from 6-week-old mice were significantly lower than those of 6-month-old mice and those of 1-year-old mice. Histologic observation revealed changes in the cochlea after age 6 months. Conventional hematoxylin and eosin (H&E) staining showed disorganization of the organ of Corti, a decrease in the number of spiral ganglion cells, and atrophy of the stria vascularis. Although H&E staining and type II collagen immunolabeling did not show obvious changes in the spiral ligament (SL), the density of connexin 26 staining was reduced in this region. Sodium-potassium-adenosinetriphosphatase immunolabeling was increased in the SL, whereas its average density was not significantly altered in the stria vascularis. These results suggest that the SL could be among the regions responsible for cochlear malfunction with aging.     

耳蜗血管纹组织块的缘细胞培养

目的 :建立豚鼠耳蜗血管纹 (SV)组织块缘细胞 (MCs)的培养方法 ,为进一步研究药物耳毒性及其作用机制奠定基础。方法 :2 6只豚鼠按SV培养时间随机分成 4组 :2 4h组 (n =8) ;72h组 (n =8) ;>72h组 (n =8) ;对照组 (新鲜SV固定组 ,n =2 )。显微解剖数段连同螺旋韧带的SV组织块 ,置于 5 %CO2 / 95 %空气的二氧化碳恒温 (37℃ )培养箱中进行培养 ,分别进行形态学和组织学观察。结果 :培养 2 4hSV组织块保持良好活性 ,其组织学结构与新鲜固定的SV结构无明显差异 ;培养 72hSV组织块与新鲜固定的SV在组织学结构方面有显著性差异 ,不能观察到正常的SV结构 ,组织结构松散 ,缘细胞从组织块离心性生长出来 ;从SV组织块培养出的缘细胞能在培养皿内存活 13d。结论 :采用组织块培养技术 ,成功地建立了豚鼠耳蜗SV组织块的缘细胞培养方法 ;培养 2 4h的SV组织块光镜下保持了良好活性和正常组织学结构 ,可用来进一步研究药物耳毒性及其作用机制。     

Decreased cochlear DNA receptor staining in MRL.MpJ-Fas(lpr) autoimmune mice with hearing loss

OBJECTIVES: Previous studies of decreased cochlear DNA binding in autoimmune mice suggested that antibodies against a cochlear cell surface DNA receptor cause autoimmune hearing loss. However, the presence of a cochlear DNA receptor has not been determined. Therefore, immunohistochemistry with an anti-DNA receptor antibody was performed on MRL.MpJ-Fas(lpr) (MRL/lpr) autoimmune mice to determine 1) which inner ear structures contain DNA receptors and 2) whether the receptor staining pattern changes as autoimmune disease progresses and hearing thresholds increase. STUDY DESIGN: A prospective study of the progression of hearing loss in autoimmune mice and correlated alterations in immunostaining for the inner ear DNA receptor. METHODS: One group of MRL/lpr mice (n = 10) was allowed to develop autoimmune disease, and auditory brainstem response (ABR) audiometry was performed at 4, 6, and 9 months of age to measure the progression of hearing loss. A second group (n = 5) was tested for ABR thresholds at 2 months of age and immediately killed to assess receptor staining before the onset of autoimmune disease and hearing loss. The inner ears from all mice were immunohistochemically stained with an anti-DNA receptor antibody, and a qualitative analysis of the staining of cochlear structures was performed. RESULTS: Auditory brainstem response audiometry revealed a significant 20- to 30-dB elevation of thresholds as systemic disease progressed. Anti-DNA receptor staining was heaviest in the spiral ligament and less intense in the spiral ganglion and cochlear nerve. Both groups showed a similar pattern of staining in these structures. The stria vascularis and hair cells also stained in both groups. However, the stria cells of normal-hearing mice showed diffuse intracellular immunoreactivity, whereas older mice displayed less staining that was confined to the cell membranes. CONCLUSIONS: The inner ears of MRL/lpr mice contain DNA receptors. Autoimmune hearing loss was correlated with weaker overall intracellular staining in the stria vascularis and hair cells but increased staining of the cell membranes. This suggested DNA receptors have impaired endocytosis and more receptors remain on the cell membrane, possibly as a result of binding by circulating autoantibodies.     

小鼠自然老化过程中耳蜗的糖代谢障碍

应用定量组织化学技术分析了ＣＢＡ和Ｃ５７ＢＬ小鼠耳蜗中糖元代谢的改变，发现１８个月和３６个月龄ＣＢＡ小鼠的毛细胞和血管纹中，糖元含量比６周龄ＣＢＡ正常小鼠明显增高，说明在自然老化ＣＢＡ小鼠耳蜗中存在糖元储积现象。     

Comparison of the quantity of cochlear melanin in young and old C57BL/6 mice

OBJECTIVE: To elucidate the functional relationship between cochlear melanin and aging. DESIGN: Melanin has been described in the cochlear labyrinth and has been suggested to protect the cochlea from various types of trauma. The quantity of melanin has been shown to change with aging in several organs; however, to our knowledge, aging changes in the cochlea have not been documented. Therefore, we chemically quantified cochlear eumelanin and pheomelanin contents and compared these in young and old C57BL/6 mice using high-performance liquid chromatography. Because melanin deposits in the cochlea present most extensively in the stria vascularis, we morphologically examined the stria using transmission electron microscopy. SUBJECTS: Cochleae from an inbred strain of C57BL/6 male and female mice; 6 at the age of 10 weeks and 5 at the age of 100 weeks were studied. RESULTS: The quantities of cochlear eumelanin and pheomelanin were 421 and 480 ng per cochlea in young mice, and 2060 and 765 ng per cochlea in old mice, respectively. Under transmission electron microscopy, the number of pigmented granules seemed to be greater in older mice compared with younger mice, especially in marginal cells. CONCLUSION: To our knowledge, our findings are the first quantitative evidence to show an age-related overexpression of cochlear melanin and an alteration in the proportion of eumelanin and pheomelanin with aging, suggesting a possible otoprotective function of eumelanin against age-related cochlear deterioration.     

TMEM16A对衰老耳蜗血管纹周细胞凋亡的作用

目的 原代培养豚鼠耳蜗血管纹毛细血管周细胞(PCs),探讨TMEM16A在耳蜗血管纹PCs上的表达变化及其对衰老耳蜗血管纹PCs凋亡的影响.方法 原代培养耳蜗血管纹PCs并鉴定;运用β-半乳糖苷酶染色确定细胞衰老模型;全细胞膜片钳技术记录PCs上CaCCs的电流变化;免疫荧光检测耳蜗血管纹PCs上TMEM16A的表达变...     

C57BL/6J 小鼠耳蜗血管纹Na-K-2Cl联合转运子-1的年龄相关性变化

目的观察不同周龄C57BL/6J(C57)小鼠听力及血管纹Na-K-2Cl联合转运子-1(Na-K-2Cl co-transporter-1,NKCC1)表达的情况。方法应用听性脑干反应(auditory brainstemresponse,ABR)分别检测4、8、16、32、48、64周龄组C57小鼠的听力;采用免疫组织化学染色法观察其血管纹NKCC1表达的变化。结果C57小鼠随年龄增大出现听力下降,自16周龄时ABR阈值出现显著性增高(P<0.05);血管纹NKCC1表达也出现年龄相关性减少,其灰度值自16周龄时显著增高(P<0.01)。结论C57小鼠血管纹NKCC1蛋白表达随年龄增长而减少,可能与年龄相关性听力损失具有一定相关性。     

The cochlea of the spontaneously diabetic mouse. I. Electron microscopic observation of KK mice

We examined the cochleae of the spontaneously diabetic KK mice by using transmission electron microscopy. At the age of 3 months, the mice started to show evidence for glycosuria and hyperglycemia, and tissue sections showed beginning cochlear pathology. The pathological changes present were found to be limited to the stria vascularis: protrusions of marginal cells, swellings of intermediate cells and widening of intercellular spaces were the main findings seen. These changes progressed with age, but were not observed in age-matched non-diabetic 57BL/6 mice. The possible mechanism of diabetes causing cochlear pathology is discussed.     

Spiral ligament and stria vascularis changes in cochlear otosclerosis: effect on hearing level.

OBJECTIVE: To investigate the effect of changes within the spiral ligament and stria vascularis on hearing in cochlear otosclerosis, we examined spiral ligament hyalinization, stria vascularis atrophy, and sensory hearing loss in cochlear otosclerosis and described changes in ion transport molecule expression. STUDY DESIGN: Retrospective. SETTING: Tertiary referral center. PATIENTS: Thirty-two cochleae from 24 temporal bone donors with histologic evidence of cochlear otosclerosis, including spiral ligament hyalinization. INTERVENTION: Audiography. MAIN OUTCOME MEASURES: Measurements of spiral ligament width, stria vascularis, and bone-conduction thresholds were compared by the amount of hyalinization. Expression of the ion transport molecules Na,K-ATPase, connexin 26, and carbonic anhydrase II were assessed by immunohistochemical techniques. RESULTS: Hyalinization most often involved the posterior basal turn (88%) and the posterior middle turn (27%). Spiral ligament hyalinization correlated significantly with stria vascularis atrophy in the posterior middle turn of the cochlea (rho = -0.63, p < 0.01). There was a trend toward a significant association in the posterior basal turn (rho = -0.31, p < 0.08). Bone-conduction thresholds at 2,000 and 4,000 Hz were significantly associated with the amount of stria vascularis atrophy (rho = -0.44, -0.40, p < 0.05). In addition, we observed decreased immunostaining for both carbonic anhydrase II with Type I fibrocytes and Na,K-ATPase with stria vascularis and Type II and Type IV fibrocytes of the spiral ligament in cochlear otosclerosis sections compared with normal cochlea. Na,K-ATPase staining within the stria vascularis was further decreased in the presence of spiral ligament hyalinization. No significant differences were seen with connexin 26 immunostaining. However, immunostaining results were somewhat inconsistent. CONCLUSION: These data suggest that spiral ligament structure and function are essential for stria vascularis survival. In addition, dampened expression of ion transport molecules within the spiral ligament and stria vascularis may disrupt potassium ion recycling, resulting in loss of endocochlear potential and sensory hearing loss.