小鼠耳蜗Na-K-2Cl联合转运子-1的定位及其缺失后的耳蜗组织学改变

目的探讨耳蜗钾循环途径中Na-K-2Cl联合转运子-1(Na-K-2Clcotransporter-1,NKCC1)在小鼠耳蜗的分布及NKCC1基因敲除后耳蜗组织学的改变。方法选用10只C57BL/6J小鼠((NCKK1 / )和5只NKCC1基因敲除小鼠(NKCC1-/-),应用听性脑干反应(auditorybrainstemresponse,ABR)分别检测NCKK1 / 小鼠和NKCC1-/-小鼠的听功能,采用免疫组织化学及甲苯胺蓝染色的方法观察NKCC1在NCKK1 / 小鼠耳蜗的定位及NKCC1-/-小鼠耳蜗组织学的变化。结果NCKK1 / 小鼠ABR平均阈值为31±5.36dBSPL,而NKCC1-/-小鼠听力完全丧失。NKCC1在NCKK1 / 型小鼠耳蜗主要分布在血管纹上皮(边缘细胞)和螺旋韧带下部纤维细胞,在纹上区和螺旋缘处的纤维细胞中也有适度表达;NKCC1-/-小鼠耳蜗前庭膜塌陷,中阶完全消失,内毛细胞、外毛细胞、支持细胞减少,Corti隧道消失。结论NKCC1在耳蜗的定位与耳蜗钾循环密切相关,NKCC1缺失会导致耳蜗正常结构的破坏,继而影响耳蜗生理功能。     

小鼠耳蜗血管纹Na-K-2Cl联合转运子1在顺铂耳毒性发生时的改变

目的研究顺铂(cis-dichlorodiammine platinum,Cisplatin)耳毒性发生后耳蜗血管纹Na-K-2Cl联合转运子1(NKCC1)的表达情况,并初步探讨其机制。方法选取健康CBA/CaJ小鼠20只,随机分为对照组和实验组各10只,实验组动物连续腹腔注射顺铂3.5mg.kg-1.d-1,建立顺铂耳毒性小鼠模型,对照组注射等量生理盐水。以听性脑干反应(ABR)阈值作为评价听功能的指标,检测给药前后小鼠听功能的改变,并采用免疫组织化学(SP法)结合免疫荧光实验技术,观察对照组和实验组小鼠腹腔注射顺铂前后耳蜗血管纹NKCC1表达的变化。结果NKCC1在小鼠耳蜗血管纹主要表达于边缘细胞,而顺铂作用后血管纹边缘细胞的NKCC1表达明显减弱,图像分析显示两组平均灰度值差异有显著统计学意义(P<0.01)。结论小鼠顺铂耳毒性作用后血管纹边缘细胞NKCC1的表达量明显减弱,这可能是顺铂耳毒性发生机制中的一个重要环节。     

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。     

耳蜗钾循环中Na-K-2Cl与听觉生理关系的研究进展

耳蜗钾循环对维持正常听觉生理功能具有重要作用.耳蜗钾循环途径中涉及诸多离子通道,本文就其中的Na-K-2Cl联合转运子(NKCC)-1与听觉生理关系的研究进展综述如下.     

新生小鼠膜迷路耳蜗外侧壁的组织培养

目的培养小鼠耳蜗螺旋韧带/血管纹来源的细胞,为体外研究提供细胞模型。方法显微解剖新生小鼠耳蜗螺旋韧带/血管纹组织,组织块外植培养,胰蛋白酶消化分离细胞,免疫组织化学染色,原位透射电镜观察鉴别细胞的来源。结果自外植耳蜗螺旋韧带/血管纹组织生长出上皮样细胞及成纤维样细胞。前者呈典型的上皮细胞形态,表达细胞角蛋白,并具血管纹边缘细胞的超微结构特征。后者呈成纤维细胞形态,表达波形蛋白,具有耳蜗螺旋韧带成纤维细胞的超微结构特征。结论培养出小鼠耳蜗血管纹边缘细胞及螺旋韧带成纤维细胞来源的原代上皮细胞及传代成纤维细胞,为体外研究提供了细胞模型及方法。     

卡那霉素对三种小鼠耳毒性比较及对血管纹Na-K-2Cl联合转运子1表达的影响

目的建立小鼠氨基糖甙类抗生素（aminoglycoside antibiotics，AmAn）耳毒性模型，探讨在不同种小鼠中的AmAn耳毒易感性及其对耳蜗血管纹Na—K-2Cl联合转运子-1（Na-K-2Cl cotransporter-1，NKCC1）表达的影响。方法将72只C57BE／6J、CBA／CaJ、NKCC1＋／-小鼠各自随机分为A、B、C、D4组。A组：卡那霉素组；B组：卡那霉素＋2，3-二羟基苯甲酸组；C组：2，3-二羟基苯甲酸组；D组：生理盐水组。各组连续用药14d。各组动物在用药前、用药后第14天及用药后第35天行脑干诱发电位（auditory brainstem response，ABR）检测听功能；耳蜗琥珀酸脱氢酶组织化学染色观察耳蜗形态学变化；免疫组化法观察血管纹NKCC1表达的变化。结果①A组小鼠ABR闽值明显提高（P〈0．01）并伴随外毛细胞的减少；②B组小鼠ABR阈值变化明显小于A组（P〈0．01），外毛细胞的损害也明显减轻；③A组小鼠耳蜗血管纹NKCCl表达减弱，与D组比较有明显差异（P〈0．01），而B组小鼠血管纹NKCC1表达较A组增强（P〈0．01）；④3种小鼠中CBA／CaJ小鼠对AmAn最敏感，C57BE／6J和NKCC1＋／-小鼠对AmAn的易感性无明显差异。结论应用卡那霉素可建立小鼠AmAn耳毒性模型；卡那霉素可抑制血管纹NKCC1的表达；2，3-二羟基苯甲酸拮抗AmAn耳毒性的途径之-可能是通过减轻AmAn对血管纹NKCC1的抑制作用；具有年龄相关性听力损失特性的小鼠对AmAn耳毒作用并不易感。     

KCNQ1在小鼠耳蜗血管纹的表达及在听觉中的意义

目的探讨KCNQ1在耳蜗侧壁血管纹的表达及其在听觉中的作用。方法以不同基因型小鼠KC-NQ1-/-(突变纯合子)、KCNQ1 /-(杂合子)和KCNQ1 / (野生型)以及C57BL/6J小鼠为实验对象,采用免疫组织化学和ABR检测技术,检测KCNQ1在小鼠耳蜗血管纹的表达及其听力。结果KCNQ1蛋白阳性颗粒集中在小鼠耳蜗血管纹边缘细胞顶膜。KCNQ1 / 小鼠的听力正常,短声ABR的阈值为36.67±7.13dBSPL;KCNQ1 /-小鼠听力低于同窝KCNQ1 / 野生型鼠,短声ABR的阈值为38.25±9.35dB SPL;KCNQ1-/-小鼠呈现全聋,ABR在100dB SPL时仍无反应。结论KCNQ1是位于耳蜗侧壁血管纹边缘细胞的重要通道蛋白,在维系耳蜗听觉功能中有重要作用。KCNQ1通道蛋白的缺失或功能受限可以不同程度地影响耳蜗的听觉功能。     

Na-K-2Cl联合转运子-1和α2Na,K-ATP酶在耳蜗钾离子循环中的作用及与听觉功能的关系

目的 应用Na-K-2Cl联合转运子-1(Na-K-2Cl Co-transporter 1,NKCC1)-/-、NKCC1+/-、α2Na,K-ATP酶+/-和NKCC1+/-/α2Na,K-ATP酶+/-等不同基因型小鼠作为实验平台,对耳蜗钾离子循环模式与听觉功能进行研究,检验NKCC1和α2Na,K-ATPase在耳蜗钾循环中的地位和作用.方法 应用NKCC1-/-、NKCC1+/-和α2Na,K-ATPase+/-等基因敲除和转基因小鼠,同时培育NKCC1+/-/α2Na,K-ATPase+/-双半拷贝基因小鼠,采用听性脑干反应和耳蜗内电位检测技术对小鼠的听觉功能进行检测.应用NKCC1通道阻断剂速尿和Na,K-ATP酶通道阻断剂哇巴因,对Castel鼠系进行通道阻断-听觉功能实验,进一步在小鼠体内检测耳蜗钾循环模式,对内耳钾循环与听觉生理之间的关系进行印证.结果 NKCC1+/-小鼠和α2Na,K-ATP酶+/-小鼠的听性脑干反应短声阈值(声压级)分别为(38.49±12.29)dB和(53.32±7.62)dB,与野生型小鼠的(23.13±3.78)dB比较均有提高,差异有统计学意义(t值分别为3.559和10.267,P＜0.05).NKCC1+/-小鼠和α2Na,K-ATP酶+/-小鼠的耳蜗内电位值分别(78±7)mV和(71±14)mV,分别低于野生型小鼠的(98±16)mV.NKCC1+/-/α2Na,K-ATP酶+/-小鼠听性脑干反应短声阈值为(24.14±8.83)dB,低于α2Na,K-ATPase+/-小鼠和NKCC1+/-小鼠,差异有统计学意义(t值分别为6.128和2.255,P＜0.05).注射速尿后的Castel小鼠听性脑干反应听阈明显升高,与注射前比较其差异有统计学意义(t=12.162,P＜0.05);注射哇巴因后的Castel小鼠也出现听阈升高(t=7.644,P＜0.05).而次序注射哇巴因和速尿后,Castel小鼠听性脑于反应听阈明显低于单独注射速尿(t=4.515,P＜0.01).结论 NKCC1和α2Na,K-ATP酶是耳蜗钾循环中的关键通道,任何一通道蛋白出现功能失衡均可影响内淋巴钾离子浓度及耳蜗内电位的维持,进而影响听觉功能.NKCC1和α2Na,K-ATP酶在耳蜗钾循环诸通道中处于一种限制性动态平衡关系,在内耳钾代谢和耳蜗听觉功能的发挥中具有重要意义.本实验在小鼠实体中验证了NKCC1和α2Na,K-ATP酶在内耳钾循环径路中的重要作用,同时也模拟了内耳钾循环模式.     

醋酸泼尼松龙对豚鼠耳蜗血管纹内Na＋/K＋/2Cl-联合转运蛋白的影响

目的：观察醋酸泼尼松龙对豚鼠耳蜗血管纹边缘细胞内Na＋/K＋/2Cl-联合转运蛋白的影响。方法筛选健康白色红目豚鼠40只,随机分成醋酸泼尼松龙组和对照组。利用糖皮质激素对醋酸泼尼松龙组豚鼠制造诱发性肾虚动物模型,按50mg/（kg·d）的剂量每日肌注醋酸泼尼松龙注射液,对照组则每日肌注生理盐水0.3ml/只,共17天。造模结束后,进行ABR阈值测试及90dBSPL给声强度下Ⅲ波潜伏期测试,同时进行免疫组化染色及Na＋/K＋/2Cl-联合转运蛋白积分光密度值（IOD值）测量。结果注射后,醋酸泼尼松龙组豚鼠ABR阈值显著提高,且90dBSPL给声强度下Ⅲ波潜伏期明显延后,两者与对照组之间有显著性差异（P〈0.01）。且与对照组相比,醋酸泼尼松龙组豚鼠耳蜗血管纹Na＋/K＋/2Cl-联合转运蛋白显著降低（P〈0.01）,免疫组化反应明显减弱。结论经醋酸泼尼松龙注射后,豚鼠出现类似“肾虚”的证候,引起耳蜗血管纹边缘细胞中Na＋/K＋/2Cl-联合转运蛋白表达减少,可能是导致听觉功能的减退原因之一。     

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.     

Permanent threshold shift caused by acute cochlear mitochondrial dysfunction is primarily mediated by degeneration of the lateral wall of the cochlea

Mitochondrial dysfunction in the cochlea is thought to be an important cause of sensorineural hearing loss. Recently, we have established a novel rat model with acute hearing impairment caused by exposure to the mitochondrial toxin 3-nitropropionic acid (3-NP) to analyze the mechanism of cochlear mitochondrial dysfunction. Both permanent and temporary threshold shifts were observed in this model depending on the amount of 3-NP used to induce hearing impairment. In this study, we demonstrate cochlear morphological changes in the permanent threshold shift model. Marked degeneration was detected in type 2 fibrocytes in the spiral prominence, type 4 fibrocytes in the spiral ligament, marginal cells and intermediate cells in the stria vascularis 3 h after 3-NP administration; these changes were progressive for at least 14 days. Less prominent degeneration was detected in type 1 and type 3 fibrocytes in the spiral ligament. These results indicate that permanent threshold shift caused by acute cochlear mitochondrial dysfunction is primarily mediated by cellular degeneration in the lateral wall of the cochlea, and suggest that therapy of cochlear hearing loss due to acute energy failure may be achieved through protection and regeneration of the cochlear lateral wall.     

正常豚鼠内耳水通道蛋白的表达及意义

目的：检测正常豚鼠内耳组织中水通道蛋白（aquaporins,AQPs）的表达,探讨其在内耳液体平衡中的意义.方法：用免疫组织化学方法,以兔抗大鼠AQP0、1、2、3、5、7、8的多克隆抗体,检测正常豚鼠内耳组织中水通道蛋白亚型0、1、2、3、5、7、8的表达.结果：水通道蛋白亚型0、1、2、3、5、7、8在豚鼠内耳有不同程度、不同模式的表达,其中AQP0仅在血管纹上皮细胞、螺旋神经节细胞有较弱的表达,AQP1的分布见于包绕骨迷路、内淋巴囊、内淋巴管的纤维细胞,基底膜鼓阶面细胞、螺旋韧带纤维细胞、螺旋缘纤维细胞、Corti器、内外螺旋沟、血管纹、椭圆囊壁、球囊壁、螺旋神经节细胞等.AQP2表达在血管纹、Corti器、螺旋神经节细胞和内淋巴囊中.AQP3、7、8的分布类似,在螺旋神经节和包绕膜迷路的组织中均有表达,其中Corti器、内外螺旋沟、血管纹、螺旋神经节表达较强,在螺旋韧带、螺旋缘纤维细胞表达较弱.AQP5则在Corti器、内外螺旋沟、螺旋神经节细胞表达较强,在螺旋韧带纤维细胞表达稍弱.结论：在正常豚鼠内耳中,尤其是膜迷路中有多种水通道蛋白亚型,以不同的方式表达,他们可能在维持膜迷路液体平衡中起着协同作用.     

Distribution and significance of endothelin 1 in guinea pig cochlear lateral wall

Endothelin 1 is a vasoconstrictive peptide with many biological functions. To investigate the distribution of endothelin 1 in guinea pig cochlear lateral wall and the significance of endothelin 1 in maintaining cochlear homeostasis, the immunohistochemistry avidin biotin complex method was applied by using rabbit anti-endothelin 1 polyclonal antibody as primary antibody. Endothelin-1-like activities were detected in the marginal cells, spiral prominence epithelial cells, outer sulcus cells, stria vascularis capillaries, basal cells and spiral ligament fibrocytes. These results suggest that endothelin 1 may play an important role in maintaining cochlear homeostasis.     

Ultrastructural study of cytochemical localization of carbonic anhydrase in the inner ear

Vibratome sections were stained for cytochemical localization of carbonic anhydrase (CA) activity in vestibular neuro-epithelium, spiral ligament and spiral limbus. The new finding is the localization of reaction products in the interdental cells of the spiral limbus, Claudius' cells, mesothelial cells of the lower border of spiral ligament, vestibular sensory cells and perilymphatic cells, which have not earlier been proved to have CA activity. The interdental cells showed the products only on the basolateral infoldings. Claudius' cells showed prominent products in the microvilli. In the vestibular sensory cells, the products were present only in the stereocilia and cuticular areas. The perilymphatic fibrocytes under the vestibular sensory epithelium, like the fibrocytes of the spiral ligament, revealed diffuse products throughout the whole cell. In the vestibular supporting cells and transitional cells, the reaction products were localized diffusely in the cytosol, but not in the secretory granules. In the long cell projections of the transitional cells, type II fibrocytes at spiral prominence, mesothelial cells at the uppermost region of the spiral ligament and Borghesan's zone, the localization of the reaction products was the same as that of the basolateral infoldings of the vestibular dark cells and marginal cells of stria vascularis shown previously.