SOD1基因缺陷型小鼠耳蜗毛细胞和螺旋神经节及神经纤维的定量观察

定量观察了出生后１３个月的先天缺失ＳＯＤ１基因小鼠的耳蜗毛细胞以及螺旋神经蕞和疆孔内的神经纤维,并与同龄野生型和出生后２个月的野生型小鼠进行了比较。发现毛细胞和螺旋神经节的缺损约为５０％,神经纤维的减少则超过５０％,提示由于与铜和锌相结合的过氧化物歧化酶的缺失导致了耳蜗神经与终器的严重退变。     

豚鼠耳蜗螺旋神经节钙调素的分布

观察正常豚鼠耳蜗螺旋神经节钙调素的分布，因为作为真核细胞中最重要的Ｃａ＾２＋受体－－钙调素在听觉径路上的分布和功能尚未见报道。     

心钠素在豚鼠耳蜗螺旋神经节中的分布及定位

心钠素在豚鼠耳蜗螺旋神经节中的分布及定位陈合新邱建华王锦铃有报道，正常耳蜗血管纹组织中存在有ＡＮＰ免疫反应（ＩＲ）物质，并提出血管纹中的ＡＮＰ可能有调节耳蜗血流量和内淋巴液生成的作用［１］。我们采用免疫细胞化学ＡＢＣ法结合免疫电镜技术，探讨ＡＮＰ在耳...     

氨基甙类抗生素对豚鼠耳蜗螺旋神经节细胞损伤的透射电镜观察

用庆大霉素、卡那霉素分别给两组豚鼠肌注,在给药7天、20天、35天后处死取标本切片。在透射电镜下观察到耳蜗螺旋神经节细胞的变化为:早期线粒体、高尔基体变性;随着给药时间的延长,细胞内有电子密度高的物质沉积,并逐渐增多。我们认为氨基甙类药物对耳蜗螺旋神经节细胞有直接毒害作用,并且是其致聋机理之一。     

小鼠耳蜗螺旋神经节细胞Ih电流的研究

目的了解小鼠耳蜗螺旋神经节细胞超极化激活阳离子通道电流（Ih电流）的基本电生理学特性。方法应用全细胞构型电压钳制技术,采用不同的阻断剂,记录Ih电流。结果实验记录到了Ih电流,对BaCl2不敏感,但可被5mMCsCl抑制,冲洗后电流恢复,符合Ih电流的药理学特点,其反转电位为-40．5±7．2my,二分之一最大活化电压（V1／2）为-103．3mv,斜率（K）为10．5;在-160mv钳制电压条件下其活化过程符合二次幂方程,时间常数分别为66．2ms和403．7ms,不同部位之间Ih电流的活化时间常数无明显差异（P〉0．05）。结论Ih电流对不同部位耳蜗螺旋神经节细胞完成其功能所起的作用可能是相似的,但需要进一步的深入研究。     

氨基甙类抗生素对豚鼠耳蜗螺旋神经节细胞损伤的透射电镜观察

用庆大霉素、卡那霉素分别给两组豚鼠肌注，在给药7天、20天、35天后处死取标本切片。在透射电镜下观察到耳蜗螺旋神经节细胞的变化为：早期线粒体、高尔基体变性；随着给药时间的延长，细胞内有电子密度搞的物质沉积，并逐渐增多。我们认为氨基甙类药物对耳蜗螺旋神经节细胞有直接毒害作用，并且是其致聋机理一。     

豚鼠螺旋神经节谷氨酸阳性神经元向耳蜗背核的投射

用豚鼠耳蜗背侧核注入６μｌ０．３ｇ／Ｌ辣根过氧化物酶（ＨＲＰ）与螺旋神经节（ＳＧ）谷氨酸（Ｇｌｕ）免疫反应相结合的双标方法。研究ＳＧ内Ｇｌｕ阳性神经元的投射，结果表明豚鼠ＳＧⅠ型及Ⅱ型Ｇｌｕ阳性神经元直接向耳蜗背核投射，并提示ＳＧ内可能还存在含其它神经信息物质的神经元并向耳蜗核投射。     

冲击波作用下豚鼠耳蜗螺旋神经节细胞PARP的表达

目的观察气体冲击致豚鼠耳蜗损伤后耳蜗螺旋神经节细胞PARP的表达。方法20只豚鼠随机分为2组,实验组用YBD-2000型冲击波发生器对豚鼠耳蜗致伤,实验前后测试听力,12h后处死动物制作耳蜗标本,免疫组化法测定耳蜗螺旋神经节细胞PARP的表达。结果ABR:实验组听性脑干反应阈值(ABR阈值为50.94±5.98)较正常对照组(ABR阈值为5.60±1.78)明显上升(P<0.01),听力下降明显。免疫组化显示:实验组耳蜗螺旋神经节细胞PARP表达阳性,对照组无阳性表达,愈近底回愈多,愈近顶回则愈少。结论PARP在气体冲击致豚鼠耳蜗螺旋神经节细胞损伤后呈阳性表达,提示耳蜗螺旋神经节细胞凋亡在冲击波致聋的发病机制中起重要作用。     

应用胰蛋白酶分离豚鼠耳蜗内毛细胞

目的：采用胰蛋白酶孵育后机械分离法以获得单离的豚鼠耳蜗内毛细胞。方法：豚鼠被迅速断头处死，暴露耳蜗，在解剖显微镜下去除耳蜗侧壁，经胰蛋白酶消化并轻轻吹打，以获得单离的豚鼠耳蜗内毛细胞。静置后在倒置相差显微镜下观察。结果：本法每侧耳分离出活性好的内毛细胞约5～20个，多数分离的内毛细胞能存活5h左右。结论：此技术能提供足量的单离内毛细胞，用于内毛细胞的电生理性质等研究。     

Projection of spiral ganglion glutamate immunoreactive positive neurons into dorsal cochlear nucleus in guinea pigs

Ｐｒｏｊｅｃｔｉｏｎｏｆｓｐｉｒａｌｇａｎｇｌｉｏｎｇｌｕｔａｍａｔｅｉｍｍｕｎｏｒｅａｃｔｉｖｅｐｏｓｉｔｉｖｅｎｅｕｒｏｎｓｉｎｔｏｄｏｒｓａｌｃｏｃｈｌｅａｒ　ｎｕｃｌｅｕｓｉｎｇｕｉｎｅａｐｉｇｓＱｉａｏＬｉ（乔莉）；ＱｉｕＪｉａｎｈｕａ（邱...     

谷氨酸钠对新生豚鼠耳蜗螺旋神经节的毒性损伤

目的研究谷氨酸钠不同用药剂量对新生豚鼠耳蜗螺旋神经节细胞及听力的影响,探索稳定而可靠的谷氨酸钠耳聋模型.方法豚鼠随机分成四组,每组(G0,G1,G2,G4)分别按0,1,2,4 g*kg-1*d-1,ip.给予谷氨酸钠(Glutamate,G),连续7d,停药后饲养35d. 测耳廓反射以及脑干听觉诱发电位;后取耳蜗,纵向石蜡切片,焦油紫染色、观察.结果 G0组死亡率为0/10,听阈为43.5±3.4 dB,平均细胞密度为4345.7±241.4个/mm2;G1组死亡率为2/10,听阈为43.8±9.4 dB,细胞密度为4215.4±295.2个/mm2;G2 组死亡率为4/10,听阈为67.3±23.3 dB,细胞密度为1997.5±1019.8个/mm2 ;G4组死亡率为20/20 .经方差分析,G2组与其他组比较,差异显著,P<0.01,GO组与G1组,差异无显著性,P>0.05.结论谷氨酸钠对新生豚鼠毒性损伤存在剂量依赖关系,2g*kg-1*d-1,ip.可引起均匀一致的耳蜗螺旋神经节细胞的消失,伴明显听力下降,死亡率较低.     

Cochlear function after selective spiral ganglion cells degeneration induced by ouabain

Background Ouabain, a cardiac glycoside that specifically binds to Na/K-ATPase and inhibits its activity, was applied to gerbils to develop a method for studying auditory neuropathy. Methods Ouabain was applied to the round window of the cochlea in each gerbil by using a piece of gelfoam with 3 μl or 24 μl （1 mmol/L） ouabain solution. The changes of the threshold of auditory brainstem response, cochlear function round window electrocochleography, as well as the morphological changes of the spiral ganglion cells of the cochlea were observed after application of ouabain for 24 hours or 96 hours. Results In ouabain treated gerbils, auditory brainstem response and compound action potential thresholds showed either elevation or no response at all. However, the thresholds of cochlear microphonic and distortion product otoacoustic emissions were not affected. Degeneration and necrosis of some spiral ganglion cells in ears with applications of ouabain （24 hours, 3 μl, 1 mmol/L; 96 hours, 24 μl, 1 mmol/L ouabain）. The number of spiral ganglion cells was decreased （24 hours, 3 μl, 1 mmol/L ouabain） or near to a total loss （96 hours, 24 μl, 1 mmol/L ouabain）. Conclusions These results indicate a high degree of independence between the spiral ganglion ceils and the outer hair cell systems in the cochlear transduction mechanism. The method used in this study would provide a valuable tool for studying auditory neuropathy.     

Adenovirus-mediated human β-nerve growth factor gene transfer has a protective effect on cochlear spiral ganglion after blast exposure

Objective：To study whether adenovirus-mediated human β-nerve growth factor （Ad-hNGFβ） gene has any protective effect on blast hearing impairment. Methods：Deafness was induced by blast exposure （172.0 dB） in 30 healthy guinea pigs. On day 7 of blast exposure, Ad-hNGFβ was infused into the perilymphatic space of 20 animals as the study group （hNGFβ group）, and artificial perilymph fluid （APF） was infused into the perilymphatic space of the other 10 animals as the control group. At weeks 1, 4 and 8 after blast exposure, the animals were sacrificed and the cochleae were removed for immunohistochemical and HE stainings. Results： Expression of Ad-hNGFβ protein was detected in each turn of the cochlea at the 1st week, with almost equal intensity in all turns. At the 4th week, the reactive intensity of the expression of Ad-hNGFβ protein decreased. At the 8th week, no expression was detectable. The results of HE staining showed that the amount of spiral ganglions in hNGFβ group was significantly greater than that of the control group at week 4 （P〈0.01）. Conclusion： Ad-hNGFβ can be expressed at a high level and for a relatively long period in the blast impaired cochlea, suggesting that Ad-hNGFβ has a protective effect on cochlear spiral ganglion cells after blast exposure and the efficient gene transfer into cochlea had been achieved without toxicity.     

Correlation of PDCD5 and apoptosis in hair cells and spiral ganglion neurons of different age of C57BL/6J mice

This study examined the expression pattern of programmed cell death 5 (PDCD5) in co-chlear hair cells and spiral ganglion neurons (SGNs) and its association with age-related hearing loss in mice.Sixty C57BL/6J (C57) mice at different ages were divided into four groups (3,6,9 or 12 months).PDCD5 expression was detected by using immunohistochemistry,real-time PCR and Western blot.Morphological change of the cochleae was also evaluated by using immunoassay.The results showed that the expression of PDCD5 had a gradual increase with ageing in both protein and RNA levels in C57 mice,as well as gradually increased apoptosis of cochlear hair cells and SGNs.In addition,we also found that caspase-3 activity was enhanced and its expression was enhanced with ageing.It is implied that overexpression of PDCD5 causes the increase in caspase-3 activity and the subsequent increase of apoptosis in cochlear hair cells and SGNs,and thereby plays a role in the pathogenesis of presbycusis.Thus,PDCD5 may be a new target site for the treatment and prevention of age-related hearing loss.     

丁胺卡那霉素对豚鼠耳蜗毛细胞凋亡及听力阈值的影响

目的探讨丁胺卡那霉素作用于耳蜗系统时毛细胞凋亡现象及其在听力损伤中的作用。方法15只豚鼠随机分为3组,各组肌内注射丁胺卡那霉素400mg·kg-1·d-1,分别于用药1d,3d,6d后处死。处死前检测其听脑于反应(auditorybrainstemresponses,ABR)的变化,并利用光镜和TUNEL标记技术检测耳蜗毛细胞发生凋亡的情况。结果①豚鼠肌内注射丁胺卡那霉素1d后耳蜗毛细胞即出现凋亡现象,连续用药3～6d,毛细胞凋亡呈强阳性表达;②耳蜗毛细胞凋亡出现的早期豚鼠听力阈值无明显改变,连续用药6d后听力阈值则明显提高。结论①丁胺卡那霉素作用于耳蜗毛细胞可引起毛细胞凋亡,细胞凋亡是豚鼠耳蜗毛细胞损伤的一条途径;②丁胺卡那霉素耳毒性作用机制可能与其引起耳蜗毛细胞凋亡有关。     

新生豚鼠谷氨酸钠内耳螺旋神经节损伤模型

目的　研究谷氨酸钠不同用药剂量对新生豚鼠耳蜗螺旋神经节细胞及听力损伤的程度 ,以探索稳定而可靠的谷氨酸钠耳聋模型 .方法　豚鼠随机分成 4组 ,每组 (G0 ,G1,G2 ,G4 )分别按 0 ,1,2 ,4g·kg- 1 ·d- 1 ,ip给予谷氨酸钠 (Gluta mate ,G) ,连续 7d ,停药后饲养 35d .处死前测其耳廓反射以及脑干听觉诱发电位 .后取耳蜗 ,纵向石蜡切片 ,焦油紫染色 ,光镜观察 .结果　G0组死亡率为 0 10 ,听阈为 (43 5± 3 4 )dB ,平均细胞密度为 (4345 7± 2 4 1 4 )个·mm- 2 ;G1组死亡率为2 10 ,听阈为 (43 8± 9 4 )dB ,细胞密度为 (42 15 4± 2 95 2 )个·mm- 2 ;G2组死亡率为 4 10 ,听阈为 (6 7 3± 2 3 3)dB ,细胞密度为 (1997 5± 10 19 8)个·mm- 2 ;G4组死亡率为 2 0 2 0 .经方差分析 ,F检验 ,G2组与其他组比较 ,差异显著 ,P <0 0 1,GO组与G1组 ,差异无显著性 ,P >0 0 5 .结论　谷氨酸钠对新生豚鼠毒性损伤存在剂量依赖关系 ,2g·kg- 1 ·d- 1 ,ip可引起豚鼠均匀一致的耳蜗螺旋神经节细胞的消失 ,听力下降明显 ,死亡率较低 ,模型较为稳定 .