神经营养因子对噪声引起豚鼠耳蜗外毛细胞损伤的防护作用

目的 定量观察胶质细胞源性神经营养因子(glial cell ine-derived neurotrophic factor,GDNF)和神经营养-3(neurotrophin-3,NT-3)对噪声引起豚鼠耳蜗外毛细胞损伤的防护作用。方法 将微渗透压泵埋置于豚鼠背部,经固定于耳蜗底回鼓阶内的改良微导管将GDNF(100ng/ml)和NT-3(2.5μg/ml)的混合液缓慢注入12只豚鼠左侧内耳,以左侧内耳灌注人工外淋巴液的9只豚鼠为对照,检测噪声暴露后豚鼠听功能和耳蜗外毛细胞形态、数量的变化。结果 噪声暴露10天后,实验组手术耳和非手术耳的脑干诱发电反应阈值低于对照组(P<0.05,p<0.01)。毛细胞表皮板和纤毛肌动蛋白荧光染色计数发现,实验组手术耳和非手术耳的外毛细胞缺失率低于对照组(p<0.001,p<0.01)。毛细胞核荧光染色计数发现,实验组手术耳和非手术耳的外毛细胞核肿胀率低于对照组(p<0.01,p<0.01)。结论 GDNF和NT-3对噪声引起豚鼠耳蜗外毛细胞损伤具有较好的防护作用。     

白噪声对豚鼠耳蜗核一氧化氮合酶活性的影响

采用硫辛酰胺脱氢酶组织化学方法及图象分析技术，研究白噪声暴露后豚鼠耳蜗核一氧化氮合酶（ＮＯＳ）神经元及ＮＯＳ活性的变化与听阈的关系，探讨豚鼠耳蜗核ＮＯＳ神经元在白噪声损伤过程中可能的作用。结果表明，白噪声暴露后耳蜗核ＮＯＳ阳性神经元的数量及染色强度明显增加，２周达到高峰，３￣４周持续高表达，至５周有所恢复，仍高于正常水平。白噪声暴露后７ｄ以内，耳蜗核ＮＯＳ活性与ＡＢＲ阈值有分离现象，７ｄ后，ＮＯＳ     

噪声刺激对耳蜗一氧化氮合酶的影响

目的：探讨一氧化氮（ＮＯ）在噪声性聋发病中的作用。方法：用中高频连续稳态噪声制作噪声性聋的动物模型,用ＮＡＤＰＨ－黄递酶组织化学、原位杂效和Ｎｏｒｔｈｅｒｎ印迹法,观察噪声刺激对耳蜗一氧化氮合酶（ＮＯＳ）表达的影响。结果：组织化学法显示ＮＯＳ主要分布于内外毛细胞、螺旋神经节细胞和血管纹边缘细胞;原位杂效法发现ＮＯＳｍＲＮＡ在内外毛细胞、螺旋神经节细胞胞浆内均可见阳性染色,但血管纹边缘细胞无阳性染色     

ATP对噪声暴露豚鼠耳蜗一氧化氮合酶活性的影响

目的 探讨ＡＴＰ对噪声暴露听力损伤的保护八月作用及对耳蜗一氧化氮合酶活性的影响。方法 制备豚鼠稳态噪声暴露听力损伤模型,应用ＮＡＤＰＨ－ｄ酶组织化学及免疫组化技术ＡＢＣ法,结合听性脑干反应（ＡＢＲ）阈值检测,研究ＡＴＰ对噪声暴露致聋豚鼠耳蜗一氧化氮合酶（ＮＯＳ）及诱生型一氧化氮合酶（ｉＮＯＳ）活性的影响。结果 ＡＴＰ对噪声暴露豚鼠的ＡＢＲ阈移有明显的抑制作用;ＡＴＰ对噪声暴露豚鼠耳蜗ＮＯＳ、ｉＮＯ     

两种神经营养因子对噪声性毛细胞损伤协同防护作用的观察

目的：观察胶质细胞源性神经营养因子（glial cell line-derved neurotrophic factor,GDNF)和神经营养素－3（neurotrophin-3,NT-3)对噪声引起毛细胞肌动蛋白损伤的协同防护作用。方法：采用改进的豚鼠耳蜗微渗透压泵慢性灌注技术,将GDNF和NT－3缓慢注入12只豚鼠左侧内耳,在左耳灌注人工外淋巴液的9只豚为对照,检测噪声暴露后豚鼠听功能和耳蜗毛细胞缺失率的变化。结果：动物术后14d(噪声暴露后10d)实验组手术耳和非手术耳的脑干诱发电位反应（auditory brainstem responses,ABR)阈值低于对照组（秩和检验,下同,P＜0．05,P＜0．01）,毛细胞表皮板和纤毛肌动蛋白荧光染色计数发现实验组手术耳和非手术耳外毛细胞缺失率均低于对照组（P＜0．001,P＜0．01）,内毛细胞缺失率也均低于对照组（P＜0．01,P＜0．01）。结论：GDNF和NT－3对噪声性聋具有较好的协同防护作用。     

两种神经营养因子对噪声性毛细胞损伤协同防护作用的观察

目的观察胶质细胞源性神经营养因子(glialcellline-derivedneurotrophicfactor,GDNF)和神经营养素-3(neurotrophin-3,NT-3)对噪声引起毛细胞肌动蛋白损伤的协同防护作用.方法采用改进的豚鼠耳蜗微渗透压泵慢性灌注技术,将GDNF和NT-3缓慢注入12只豚鼠左侧内耳,以左耳灌注人工外淋巴液的9只豚鼠为对照,检测噪声暴露后豚鼠听功能和耳蜗毛细胞缺失率的变化.结果动物术后14d(噪声暴露后10d)实验组手术耳和非手术耳的脑干诱发电位反应(auditorybrainstemresponses,ABR)阈值低于对照组(秩和检验,下同.P＜0.05,P＜0.01),毛细胞表皮板和纤毛肌动蛋白荧光染色计数发现实验组手术耳和非手术耳外毛细胞缺失率均低于对照组(P＜0.001,P＜0.01),内毛细胞缺失率也均低于对照组(P＜0.01,P＜0.01).结论GDNF和NT-3对噪声性聋具有较好的协同防护作用.     

豚鼠耳蜗一氧化氮合酶异型体的定位

目的 研究一氧化氮合酶(NOS)的异型体在豚鼠耳蜗的定位分布，以探讨一氧化氮(NO)在内耳听觉生理和病理生理机制中的作用。方法 使用特异性NOS异型体抗体，采用ABC免疫组化染色法，观察NOS异型体在正常豚鼠耳蜗的定位表达。结果 NOS Ⅰ主要分布在内骨膜、螺旋神经节的核周体、螺旋韧带和Corti’s器的细胞。NOS Ⅲ是耳蜗的主要NOS异型体免疫染色，其主要免疫染色分布于耳蜗神经、螺旋神经节核周体、螺旋韧带和耳蜗毛细血管球的内皮细胞，也见于Corti’s器的细胞和神经纤维。NOS Ⅱ在正常豚鼠耳蜗内不表达。结论 结构型NOS(cNOS)表达在耳蜗的多个部位，表明NO参与内耳的正常生理功能，包括神经突触的神经传导、耳蜗血流的调节和耳蜗的骨代谢。     

豚鼠耳蜗一氧化氮合酶的分布

目的 用组织化学法,通过观察NADPH-黄递酶的活性了解一氧化氮合酶在豚鼠耳蜗内分布。方法 经4％多聚甲醛心脏灌注固定后,取出耳蜗,经3％依地酸脱钙后,作厚10μm冰冻切片,用辅酶Ⅱ孵育液在37℃条件下孵育l小时。结果 发现在耳蜗内、外毛细胞底部与耳蜗神经末梢接头处及毛细血管球内皮细胞有明显NADPH-黄递酶活性,此外在内、外柱细胞、支持细胞、血管纹及螺旋神经节细胞也有NADPH-黄递酶活性反应。结论 NO在维持耳蜗正常神经传导及毛细血管张力中起着重要作用。     

豚鼠耳蜗一氧化氮合酶异型体的定位

目的研究一氧化氮合酶(NOS)的异型体在豚鼠耳蜗的定位分布,以探讨一氧化氮(NO)在内耳听觉生理和病理生理机制中的作用。方法使用特异性NOS异型体抗体,采用ABC免疫组化染色法,观察NOS异型体在正常豚鼠耳蜗的定位表达。结果NOS Ⅰ主要分布在内骨膜、螺旋神经节的核周体、螺旋韧带和Corti's器的细胞。NOSⅢ是耳蜗的主要NOS异型体免疫染色,其主要免疫染色分布于耳蜗神经、螺旋神经节核周体、螺旋韧带和耳蜗毛细血管球的内皮细胞,也见于Corti's器的细胞和神经纤维。NOS Ⅱ在正常豚鼠耳蜗内不表达。 结论结构型NOS(cNOS)表达在耳蜗的多个部位,表明NO参与内耳的正常生理功能,包括神经突触的神经传导、耳蜗血流的调节和耳蜗的骨代谢。     

睫状神经营养因子防治强脉冲噪声对豚鼠内耳损伤的实验 …

目的 探索应用睫状神经营养因子防治强脉冲噪声对豚鼠内耳损伤的可能性,为强脉冲噪声致聋的防治提供新的方法。方法 制作强脉冲噪声聋豚鼠模型３６只,１８只应用ＣＮＴＦ人注射３周,１８只等量的生理盐水作对照,正常对照豚鼠１８只,进行耳蜗铺片计算机图像分析毛细胞计数,螺旋神经节细胞计数、耳蜗乙酰胆碱酯酶染色铺片观察和ＡＢＲ反应阈测定。结果 正常姐、噪声暴露后２１ｄ的生理盐水对照组和ＣＮＴＦ组耳蜗毛细胞平均总     

Nitric oxide synthase inhibitor reduces noise-induced cochlear damage in guinea pigs

Conclusion. The results obtained in this study indicate that N^G-nitro-L-arginine methyl ester (L-NAME) protects cochlear damage from acoustic trauma through reducing the production of nitric oxide (NO). Objectives. This study aimed to explore whether NO synthase inhibitor L-NAME could reduce cochlear damage in acoustic trauma. Materials and methods. Seventy guinea pigs (300–350g) were divided randomly into four groups (n=20 in groups I, III, and IV; n=10 in group II). Two days consecutively and 30min before noise exposure (4kHz octave band, 115dB SPL 5h), subjects received an injection of 5ml saline/kg (groups I and III) or 10mg/kg L-NAME (groups II and IV). Sham-exposed guinea pigs were listed as groups I and II. Protection was assessed physiologically by the change in auditory brainstem response (ABR) threshold and histologically by survival of outer hair cells (OHCs). NO level of cochlear tissue was assayed 3days after noise exposure. Results. Group III showed significantly greater OHC loss, threshold shifts and NO level compared with group I and group IV. Compared with group III, noise-induced elevation in NO level in the cochlea was significantly attenuated by L-NAME (p<0.001).     

Glutamate toxicity induced degeneration of outer hair cells with a temporal increase of nitric oxide production in the guinea pig cochlea

The aim of this study was to examine the roles of glutamate (GLU) toxicity and involvement of nitric oxide (NO) in the pathogenesis of cochlear degeneration. We examined guinea pig cochleae following chronic exposure to GLU. Trypan blue extrusion and transmission electron microscopy were performed to evaluate degeneration in the organ of Corti. In parallel, nitric oxide synthase (NOS) activity was demonstrated by histochemical staining of NADPH diapholase. GLU treatment caused time-dependent degeneration of outer hair cells (OHCs) in conjunction with a temporal increase of NOS activity in the organ of Corti. This suggests that GLU may be involved in OHC degeneration under toxic conditions, with NO production possibly playing a role in this process. Received: 2 April 1998 / Accepted: 4 December 1998     

NOS在分泌性中耳炎所致感音神经性聋中的作用

目的:探讨NOS及NO在分泌性中耳炎(SOM)所致感音神经性聋(SNHL)中的作用。方法:治疗前分别抽取16例伴有SNHL的SOM患者(A组)及16例不伴有SNHL的SOM患者(B组)的中耳积液,检测两组中耳积液内NOS活性和NO含量。结果:A组中耳积液内NO含量(181.19±44.31)μmol/L明显高于B组(137.00±40.67)μmol/L(P<0.01),A组中耳积液内NOS活性(97.69±29.62)U也明显高于B组(75.50±26.99)U(P<0.05)。结论:NO可能通过直接损伤和与其他炎症递质共同作用增强局部炎症反应,在SOM所致的SNHL过程中发挥重要作用。     

一氧化氮合酶和心钠素在豚鼠耳蜗的分布

目的 观察豚鼠耳蜗局部心钠素（atral natruretc peptde，ANP）和一氧化氮合酶（nitric oxide synthase，NOS）免疫组化反应产物的分布，为研究ANP和NOS在豚鼠耳蜗局部血流、淋巴以及神经调节中的相互作用提供形态学依据。方法 采用免疫组织化学双标法检测ANP和NOS在正常豚鼠耳蜗的分布特征。结果 在耳蜗各转螺旋动脉和血管纹．螺旋缘、螺旋韧带和Corti器显示双阳性染色，螺旋神经节细胞及囊斑神经上皮细胞膜及轴突NOS阳性染色，胞质ANP阳性染色；盖膜、前庭膜阴性染色。结论 ANP和NOS在内耳血 流调节，内、外淋巴平衡调节以及神经信号传递等方面可能具有重要作用，二者之间可能存在密切的相互作用机制，其分布特点与功能密切相关。     

用电化学方法鉴别雏鸡耳蜗神经元中一氧化氮合酶的类型

目的：鉴别雏鸡耳蜗神经元中一氧化氮合酶的类型。方法：用ＣｕＰｔＣｌ６化学修饰电极,检测了离体的雏鸡耳蜗神经元在含Ｃａ＾２＋的谷氨酸、缓激肽,不含Ｃａ＾２＋的主Ｌ－精氨酸、三磷酸腺苷、乙酰胆碱、缓激肽等溶液刺激下一氧化氮的释放反应,结果：有Ｃａ＾２＋情况下谷氨酸可以诱发一氧化氮释放,其余均无释放反应,结论,雏鸡耳蜗元中的一氧化氮合酶为神经型。     

Immunoelectron microscopic localization of nitric oxide synthase III in the guinea pig organ of Corti

Nitric oxide synthase III (NOS III) was identified in the guinea pig cochlea on an ultrastructural level using a post-embedding immunolabeling procedure. Ultrathin sections of London Resin (LR) White-embedded specimens were incubated with various concentrations of a commercially available antibody to NOS III and the immunoreactivity visualized by a gold-labeled secondary antibody. Analysis of ultrathin sections of the organ of Corti in the second turn of the cochlea showed that NOS III could be localized in the endothelial cells of the blood vessels under the basilar membrane, which was comparable to its location in similar cells types in various biological systems. Besides this, NOS III was also found in the cytoplasm and in the nuclei of inner and outer hair cells. Immunoreactivity was not distributed homogeneously within receptor cells. Numerous gold particles could be identified at the border of the cuticular plates, in the middle parts of the stereocilia and in the cytoplasm. Gold-labeled anti-NOS III antibodies in these sites were seen mostly on the cytoplasmic side of the submembranous cisterns in the vicinity of mitochondria and in the central parts of the hair cells, whereas the cisterns were nearly free from any immunoreactivity. NOS III was also detected in the efferent and afferent nerve endings that were located at the basal and basolateral side of the outer hair cells. Some immunoreactivity was visible in different nerve fibers of the inner and outer spiral tunnels. Besides this, gold-labeled antibodies were also present in the cuticular plate of inner and outer pillar cells, in the cytoskeletal elements located in the apical parts of Deiters cells, forming the lamina reticularis, and in the cytoskeletal-containing region of the cytoplasm of those Deiters cells located at the basal side of the outer hair cells. The role of the NOS III immunoreactivity identified in the organ of Corti was consistent with respect to hair cell and tissue modulation. Received: 24 September 1997 / Accepted: 26 June 1998     

西地那非对豚鼠噪声性听觉损伤阈移的影响

目的 探讨西地那非(sildenafil)对豚鼠噪声性听觉损伤阈移的影响.方法 将豚鼠按随机数字表法分为对照组、噪声暴露组和西地那非给药组,每组10只.西地那非组及噪声组豚鼠在白噪声(A计权声压级110 dB)暴露1周后分别腹腔注射西地那非10 mg/(kg·d)及生理盐水4mL/(kg·d),连续给药4周.分别测试噪声暴露前1日、噪声暴露后1、2及4周听性脑干反应(ABR)阈值,并通过扫描电镜观察噪声暴露后4周豚鼠耳蜗毛细胞的形态变化.结果 噪声暴露1后,噪声暴露组豚鼠ABR阈值(声压级)平均提高19.1 dB,随着时间推移,阈移逐渐加大,暴露后4周,阈值平均提高22.0 dB;西地那非组噪声暴露后ABR阈值提高19.8 dB,给药后阈移逐渐减小,给药后4周,阈值仅平均提高4.8 dB.西地那非组与噪声暴露组相比,除噪声暴露结束后这一时间点以外,其余给药后各时间点ABR阈值差异均具有统计学意义(P值均＜0.05).扫描电镜显示,噪声组豚鼠耳蜗内、外毛细胞均出现听毛紊乱、融合及缺失;而西地那非组耳蜗病变较轻,听毛仅有轻微倒伏、融合现象.结论 西地那非能够减轻噪声对豚鼠耳蜗毛细胞的损害,降低噪声性听觉损伤引起的ABR阈值升高.     

雏鸡耳蜗中的一氧化氮合成酶分布

应用冰冻切片组织化学技术，以还原型尼克酰胺腺嘌呤二核苷酸磷酸-黄递酶特异性地确定一氧化氮合成酶（NOS）在小鸡耳蜗中存在，观察其分布情况，发现听毛细胞底部颗粒较集中，染色深，毛细胞周围亦有散在颗粒，基底乳头近端与远端染色强弱相似。阳性反应神经纤维连接毛细胞底部。螺旋神经节细胞胞浆中有大量的蓝色颗粒，细胞核无着色，这些细胞大小均匀，呈圆形或椭圆形，周围有多量阳性神经纤维，提示可能为神经性NOS。血管盖内皮细胞胞浆中酶活性较强。对这些分布特点和意义进行了讨论。