庆大霉素中毒后豚鼠耳蜗毛细胞的再生

目的：通过庆大霉素中毒后不同时间豚鼠耳蜗毛细胞变化的观察，研究哺乳动物耳蜗毛细胞受损后能否再生。方法：将60只豚鼠随机分成庆大霉素组和生理盐水对照组。应用扫描电镜（SEM）技术并结合听脑干反应（ABR）测试，观察耳蜗毛细胞情况和ABR阀值变化。结果：庆大霉素组耳蜗毛细胞在30 d时ABR阈值有明显恢复，但未达到正常水平，同时耳蜗第三转有新生的静纤毛出现。结论：庆大霉素损伤后的毛细胞可以再生。     

关节突植骨融合联合竖脊肌离断建立邻近椎间盘退行性变动物模型的初步研究

目的研究关节突植骨融合联合竖脊肌离断的方法建立邻近椎间盘退行性变动物模型可行性。方法选用日本大耳白兔24只,3个月龄,雌雄不限,体质量（2．5±0．5）kg,随机平均分成2组。实验组切除L3-4、L4-5、L5-6。双侧关节突并原位进行植骨,同时横断L1水平双侧竖脊肌;对照组只切开皮肤即缝合。术后2个月和6个月,从形态学和影像学（三维CT重建和MRI、观察腰椎融合情况和邻近椎间盘退行性变情况。结果实验组术后2个月时,L3-6。椎体关节突处骨赘增生．腰椎活动受限,腰椎后结构发生融合;6个月时,L2-3,椎间盘高度降低,含水量减少,组织学提示纤维环排列不规整并出现裂隙．发生退行性改变.对照组未见明显变化。结论应用破坏腰椎关节突并植骨联合切断双侧竖脊肌的方法,可以建立腰椎后结构融合导致邻近椎间盘退行性变的实验动物模型．为研究邻近椎间盘退行性变的发生机制奠定研究基础。     

睡眠剥夺对吗啡成瘾小鼠学习记忆能力的影响

目的:观察睡眠剥夺对吗啡成瘾小鼠的空间学习记忆能力的影响。方法:ICR小鼠40只随机分为4组(n=10):生理盐水对照组、吗啡成瘾实验组、生理盐水+睡眠剥夺对照组、吗啡成瘾+睡眠剥夺实验组。小鼠递增注射吗啡7 d建立成瘾模型后,通过睡眠剥夺箱48 h建立睡眠剥夺模型,水迷宫实验观察其学习记忆的前后差异对比。结果:与单纯吗啡成瘾组及睡眠剥夺组相比,吗啡成瘾+睡眠剥夺组与睡眠剥夺小鼠水迷宫逃避潜伏期时间明显延长(P<0.05)。结论:睡眠剥夺加重吗啡成瘾ICR小鼠的学习记忆能力的损害作用。     

电子耳蜗CIS算法听觉仿真模型语音合成方法的改进

电子耳蜗是一种替代人内耳功能的电子装置.本文基于电子耳蜗听觉仿真模型理论,通过分析电听觉和人耳听觉的差异,改进了原有的CIS语音处理算法的语音合成方法,使之更加贴近和符合临床上电子耳蜗植入者的实际听觉认知效果,并初步进行了听觉仿真试验及正常人听辨测试,结果证实了改进后模型的有效性和合理性.     

缝隙连接蛋白26和30在大鼠2型糖尿病性耳聋模型中的表达

目的 探讨缝隙连接蛋白(Cx) 26和Cx30在大鼠2型糖尿病耳蜗中的表达,及两者在2型糖尿病性耳聋发病机制中的作用.方法 60只Wistar大鼠随机分为实验组(40只)和对照组(20只);实验组以腹腔注射10 mg/L链脲佐菌素建立2型糖尿病模型,检测模型成功前及成功后第1、2、3、4、5月的听性脑干反应(ABR),...     

编码Na-K-2Cl的基因缺陷小鼠出现听觉和平衡功能障碍及内耳形态异常

目的： 培育突变型纯合子NKCC1^-/-、杂合子NKCC1^+/-及野生型NKCC1^+/+小鼠，将这3种基因型小鼠作为实验平台，研究NKCC1离子通道(Na-K-2Cl,co-transporter)在耳蜗听觉平衡功能中的作用，并观察不同基因型小鼠的内耳形态特征。方法： 利用同窝生各个基因型小鼠NKCC1^-/-（突变纯合子）、NKCC1^+/-（杂合子）和NKCC1^+/+（野生型）为实验对象，采用听觉脑干反应(ABR)和耳蜗内电位(EP)检测技术，对各基因型小鼠的听觉功能和EP进行检测；同时利用光学显微镜观察不同基因型小鼠的内耳形态变化。结果： NKCC1^+/+野生型小鼠听力正常，ABR检测的click短音阈值为［（23.13±3.78）dB,SPL］；EP为(98±16)mV。NKCC1^+/-杂合子小鼠听力低于同窝生的NKCC1^+/+野生型小鼠，ABR检测其Click短音阈值为［（38.49±12.29）dB,SPL］，EP为(78±7)mV。NKCC1^+/+和NKCC1^+/-小鼠ABR的阈值均值在各个频率的差异显著(P<0.01)；两者EP的均值差异也显著 (P<0.05)。NKCC1^-/-突变型纯合子小鼠呈现全聋，ABR各个频率在100 dB均无反应，其EP接近消失（4 mV±6 mV）。NKCC1^-/-突变型纯合子小鼠表现出听觉功能丧失和旋转为主的平衡失调。光镜下NKCC1^+/+野生型小鼠和NKCC1^+/-杂合子小鼠的耳蜗解剖结构无明显异常；NKCC1^-/-突变纯合子小鼠的耳蜗出现前庭膜塌陷、内淋巴腔缩小而致中阶完全消失，并有血管纹萎缩、Corti器缺失、螺旋神经节萎缩；且球囊和椭圆囊膜迷路失去正常结构并出现塌陷等病理改变。结论: NKCC1离子通道在内耳K⁺循环和维系内耳正常听觉平衡功能中起重要作用。NKCC1通道的缺失或功能受限，均可导致耳蜗内淋巴K⁺负荷水平，进而影响耳蜗的听觉平衡功能。     

可移植性Balb/c小鼠急性红白血病动物模型的建立

目的建立稳定的可移植性Balb/c小鼠的急性红白血病动物模型。方法将2×106个的EL9611红白血病细胞通过尾静脉输注每只Balb/c(H-2d)小鼠(n=10),体内传代建立EL9611红白血病动物模型,通过15代的连续传代观察模型的可靠性,以健康BALB/c鼠(n=4)作为正常对照。观察小鼠腹部、肝脾重量,计数实验组和正常对照组的外周血白细胞数,取发病晚期小鼠的外周血涂片行Giemsa染色观察,肝脾组织经10%甲醛固定、石蜡切片、HE染色检查,计算小鼠平均生存时间、发病率和死亡率。结果接种2×106个EL9611白血病细胞后实验组平均生存时间(MST)为(14.5±2.1)d,生存时间与正常对照组相比,P<0.01,经15代的连续传代,未见自发缓解,发病率和死亡率均为100%,无性别选择性,发病晚期小鼠出现肝脾肿大和外周血WBC升高等典型白血病的表现,死亡时肝重(2.40±0.48)g,脾重(0.84±0.20)g,与正常对照组相比,P<0.01,死亡前外周血WBC计数为(3.33±0.27)×107/mL,与正常对照组比,P<0.05,外周血中可见多量异形白血病细胞,病理检查示肝脾正常组织结构破坏,大量白血病细胞浸润。结论采用EL9611红白血病细胞2×106静脉输注体内传代的方式可建立起稳定的可移植性Balb/c小鼠的急性红白血病动物模型。     

急入高海拔环境后对听觉的影响研究

目的 通过模拟高海拔环境对急进入高原人群听力的变化进行研究,并建立动物模型研究急进高原对听觉系统的影响,为急性缺氧引起的耳聋治疗提供理论依据。方法 选择拟急进入高原的受试者,在进入高原前,受试者进入模拟海拔5 000 m的低压氧舱内适应5 h,在入舱前后进行纯音测听(测试频率为250 Hz、500 Hz、1 kHz、2 kHz、4 kHz、8 kHz)。比较受试者入舱前后纯音测听的结果,并进行统计学分析。根据此结果建立动物模型,选取健康雄性C57小鼠50只,将小鼠随机分为对照组、缺氧5 h组、缺氧10 h组、缺氧24 h组、缺氧48 h组,每组10只。低压低氧动物实验舱模拟海拔5 000 m高原环境,采用听觉脑干诱发电位(ABR)测量小鼠听力变化情况。结果 受试者入舱后听力较入舱前有一定变化,双耳听阈及大多数频率(250 Hz、500 Hz、1 kHz、8 kHz)的纯音测听阈值较入舱前升高,差异有统计学意义(P<0.05),右耳中频(2 kHz)纯音测听阈值较入舱前无显著变化(P>0.05)。在动物实验中,实验组Ⅰ、Ⅱ、Ⅲ、Ⅳ波潜伏期较对照组延长(P<0.05),Ⅴ...     

C57BL/6J小鼠耳蜗内毛细胞传入神经突触的超微结构观察

目的利用投射电镜观察C57Bl/6J小鼠耳蜗内毛细胞传入神经突触的形态和结构。方法选择发育成熟的C57Bl/6J小鼠,ABR检测听力正常后获取耳蜗标本,分别经过半薄定位和超薄连续切片观察的方法寻找观察耳蜗内毛细胞传入神经突触的形态和结构,探讨发育成熟状态下小鼠耳蜗内毛细胞突触的形态和结构特点,并进一步分析它们可能出现的区域以及与周围解剖结构的关系。结果在听力正常的C57Bl/6J小鼠的不同耳蜗内毛细胞核下区域可以观察到带状突触结构,包括ribbon、突触囊泡、突触间隙和突触后致密带等典型结构;然而有时即使是在听力正常的小鼠耳蜗内,也不能同时观察到这些结构的全部,即内毛细胞带状突触的超微结构和形态可能表现出彼此之间存在明显区别的形式。结论在听力正常的生理状态下,成熟小鼠(c57BL/6J)耳蜗内毛细胞突触的形态和结构处于动态变化之中,突触的个体形态和结构可以表现出不同的特点,而这种结构上的动态变化可能和突触功能的变化有关。     

低温等离子消融术建立兔椎间盘退变模型的实验研究

目的　探讨低温等离子消融术建立兔椎间盘退变模型的方法与可行性。 方法　新西兰大白兔24只,随机分为实验组12只,对照组12只。两组均穿刺L3/4～L5/6椎间隙,实验组采用消融30s建模,对照组单纯以穿刺针穿刺建模。分别于术前及术后4、8、12周行CR、MRI检查及病理学检查。 结果　实验组DR及MR检查至术后12周均可见退变逐步加重的征象,如椎间隙高度的丢失及T2信号逐步降低。对照组DR及MR检查4周后无明显的退变加重迹象。两组病理学检查均未见早期的髓核缺失,实验组12周可见髓核正常结构消失,椎间盘内结构紊乱。 结论　低温等离子消融术比传统单纯穿刺更易及快速建立椎间盘退变的动物模型,采用此方法建立兔椎间盘退变模型是可靠可行的。     

Hearing loss in the laminin-deficient dy mouse model of congenital muscular dystrophy

Sensorineural hearing loss is found in many inherited forms of muscular dystrophy. We investigated the dy mouse model, which has congenital muscular dystrophy due to a defect in laminin alpha 2, for evidence of cochlear dysfunction. Auditory brainstem response (ABR) audiometry to pure tones was used to evaluate 3-month-old homozygous dy/dy and age-matched C57 control mice. The average ABR thresholds to tone-burst stimuli for four frequencies (4, 8, 16, and 32 kHz) were determined and statistically compared by ANOVA. The dy/dy mice demonstrated elevated auditory thresholds ranging from 25 to 27 dB at each frequency tested (p<0.0001). Anatomic evaluations of the ears revealed pathology ranging from extensive connective tissue infiltration within the inner ear to possible minor defects in the cells of the organ of Corti. These anatomic and physiologic observations suggest that the extracellular matrix protein laminin plays a crucial role in normal cochlear function. Furthermore, the dy congenital muscular dystrophy mouse offers a novel model for evaluation of sensorineural hearing loss associated with muscular dystrophy.     

Transplantation of neural differentiated human mesenchymal stem cells into the cochlea of an auditory-neuropathy guinea pig model

The aim of this study was to determine the effects of transplanted neural differentiated human mesenchymal stem cells (hMSCs) in a guinea pig model of auditory neuropathy. In this study, hMSCs were pretreated with a neural-induction protocol and transplanted into the scala tympani of the guinea pig cochlea 7 days after ouabain injury. A control model was made by injection of Hanks balanced salt solution alone into the scala tympani of the guinea pig cochlea 7 days after ouabain injury. We established the auditory neuropathy guinea pig model using 1 mM ouabain application to the round window niche. After application of ouabain to the round window niche, degeneration of most spiral ganglion neurons (SGNs) without the loss of hair cells within the organ of Corti and increasing the auditory brain responses (ABR) threshold were found. After transplantation of neural differentiated hMSCs, the number of SGNs was increased, and some of the SGNs expressed immunoreactivity with human nuclear antibody under confocal laser scanning microscopy. ABR results showed mild hearing recovery after transplantation. Based on an auditory neuropathy animal model, these findings suggest that it may be possible to replace degenerated SGNs by grafting stem cells into the scala tympani.     

Detection and differentiation of sensorineural hearing loss in mice using auditory steady-state responses and transient auditory brainstem responses

Sensorineural hearing loss (SNHL) comprises hearing disorders with diverse pathologies of the inner ear and the auditory nerve. To date, an unambiguous phenotypical characterization of the specific pathologies in an affected individual remains impossible. Here, we evaluated the use of scalp-recorded auditory steady-state responses (ASSR) and transient auditory brainstem responses (ABR) for differentiating the disease mechanisms underlying sensorineural hearing loss in well-characterized mouse models. We first characterized the ASSR evoked by sinusoidally amplitude-modulated tones in wild-type mice. ASSR were robustly elicited within three ranges of modulation frequencies below 200 Hz, from 200 to 600 Hz and beyond 600 Hz in most recordings. Using phase information we estimated the apparent ASSR latency to be about 3 ms, suggesting generation in the auditory brainstem. Auditory thresholds obtained by automated and visual analysis of ASSR recordings were comparable to those found with tone-burst evoked ABR in the same mice. We then recorded ASSR and ABR from mouse mutants bearing defects of either outer hair cell amplification (KCNQ4-knockout) or inner hair cell synaptic transmission (Bassoon-mutant). Both mutants showed an increase of ASSR and ABR thresholds of approximately 40 dB versus wild-type when investigated at 8 weeks of age. Mice with defective amplification displayed a steep rise of ASSR and ABR amplitudes with increasing sound intensity, presumably reflecting a strong recruitment of synchronously activated neural elements beyond threshold. In contrast, the amplitudes of ASSR and ABR responses of mice with impaired synaptic transmission grew very little with sound intensity. In summary, ASSR allow for a rapid, objective and frequency-specific hearing assessment and together with ABR and otoacoustic emissions can contribute to the differential diagnosis of SNHL.     

Limitation of Conventional Audiometry in Identifying Hidden Hearing Loss in Acute Noise Exposure

PurposeThe concept of hidden hearing loss can explain the discrepancy between a listener''s perception of hearing ability and hearing evaluation using pure tone audiograms. This study investigated the utility of the suprathreshold auditory brainstem response (ABR) for the evaluation of hidden hearing loss in noise-exposed ear with normal audiograms.Materials and MethodsA total of 15 patients (24 ears) with normal auditory thresholds and normal distortion product otoacoustic emissions were included in a retrospective analysis of medical records of 80 patients presenting with histories of acute noise exposure. The control group included 12 subjects (24 ears) with normal audiograms and no history of noise exposure. Pure tone audiometry and suprathreshold ABR testing at 90 dB peSPL were performed. The amplitudes and latencies of ABR waves I and V were compared between the noise-exposed and control groups.ResultsWe found no significant difference in the wave I or V amplitude, or the wave I/V ratio, between the two groups. The latencies of ABR wave I, V, and I-V interpeak interval were compared, and no significant intergroup difference was observed.ConclusionThe results suggest that either hidden hearing loss may not be significant in this cohort of patients with acute noise exposure history, or the possible damage by noise exposure is not reflected in the ABRs. Further studies are needed to inquire about the role of ABR in identification of hidden hearing loss.     

Erratum to "Noise-induced changes of neuronal spontaneous activity in mice inferior colliculus brain slices"

The inferior colliculus (IC) in vivo is reportedly subject to a noise-induced decrease of GABA-related inhibitory synaptic transmission accompanied by an amplitude increase of auditory evoked responses, a widening of tuning curves and a higher neuronal discharge rate at suprathreshold levels. However, other in vivo experiments which demonstrated constant neuronal auditory thresholds or unchanged spontaneous activity in the IC after noise exposure did not confirm those findings. Perhaps this can be the result of complex noise-induced interactions between different central auditory structures. It was, therefore, the aim of the present study to investigate the effects of noise exposure on the spontaneous electrical activity of single neurons in a slice preparation of the isolated mouse IC. Normal hearing mice were exposed to noise (10 kHz center frequency at 115 dB SPL for 3 h) at the age of 21 days under anesthesia (Ketamin/Rompun 10:1). After one week, auditory brainstem response (ABR) recordings and extracellular single-unit recordings from spontaneously active neurons within the IC slice were performed in noise-exposed and in normal hearing control mice. Noise-exposed animals showed a significant ABR threshold shift in the whole tested frequency range and a significant lower neuronal spontaneous activity in all investigated isofrequency laminae compared to controls. In both groups, the firing rate of 80% of IC neurons (approximately) increased significantly during the application of the GABA(A) receptor antagonist Bicucullin (10 microM). The present findings demonstrate a noise-related modulation of spontaneous activity in the IC, which possibly contribute to the generation of noise-induced tinnitus and hearing loss.     

Noise-induced changes of neuronal spontaneous activity in mice inferior colliculus brain slices

The inferior colliculus (IC) in vivo is reportedly subject to a noise-induced decrease of GABA-related inhibitory synaptic transmission accompanied by an amplitude increase of auditory evoked responses, a widening of tuning curves and a higher neuronal discharge rate at suprathreshold levels. However, other in vivo experiments which demonstrated constant neuronal auditory thresholds or unchanged spontaneous activity in the IC after noise exposure did not confirm those findings. Perhaps this can be the result of complex noise-induced interactions between different central auditory structures. It was, therefore, the aim of the present study to investigate the effects of noise exposure on the spontaneous electrical activity of single neurons in a slice preparation of the isolated mouse IC. Normal hearing mice were exposed to noise (10 kHz center frequency at 115 dB SPL for 3 h) at the age of 21 days under anesthesia (Ketamin/Rompun 10:1). After one week, auditory brainstem response (ABR) recordings and extracellular single-unit recordings from spontaneously active neurons within the IC slice were performed in noise-exposed and in normal hearing control mice. Noise-exposed animals showed a significant ABR threshold shift in the whole tested frequency range and a significant lower neuronal spontaneous activity in all investigated isofrequency laminae compared to controls. In both groups, the firing rate of 80% of IC neurons (approximately) increased significantly during the application of the GABA(A) receptor antagonist Bicucullin (10 microM). The present findings demonstrate a noise-related modulation of spontaneous activity in the IC, which possibly contribute to the generation of noise-induced tinnitus and hearing loss.     

儿童感音神经性聋听觉稳态诱发反应阈与听性脑干反应阈比较

目的研究听觉稳态诱发反应(ASSR)和听性脑干反应(ABR)阈与纯音听阈的差别和相关性。方法选择74例儿童感音神经性聋患者(118耳)分别进行ASSR、ABR和电测听检查,比较ASSR、ABR反应阈及纯音听阈,同时就ASSR、ABR反应阈与纯音听阈进行相关性分析。结果 ASSR和ABR反应阈与纯音听阈均有良好的相关性。ABR的反应阈与纯音听阈阈值接近,而ASSR反应阈与纯音听阈间差值较大。ASSR反应阈与纯音听阈间的相关性要优于ABR反应阈与纯音听阈间的相关性。结论 ASSR和ABR均为较好的评估行为听阈的客观测听方法。     

Noise-induced aspartate and glutamate efflux in the guinea pig cochlea and hearing loss

Aspartate and glutamate were monitored in the scala tympani of the guinea pig cochlea using in vivo microdialysis before and during noise exposure. Moderate level broad band noise [105 dB sound pressure level (SPL), 30 min] neither altered the levels of aspartate or glutamate, nor auditory brainstem response (ABR) thresholds. High level noise exposure (135 dB SPL, 30 min) caused a large increase in aspartate (330%), a smaller increase in glutamate (150%), and a permanent ABR threshold shift of 60-75 dB between 2.0 and 12.5 kHz. Morphological analysis of the cochlea revealed a collapse of supporting structures, swelling of the afferent dendrites under the inner hair cells, and outer hair cell loss. Pretreatment with the NMDA antagonist, MK 801 (1 mg/kg body weight, i.p.) 1 h before noise exposure protected the afferent dendrites from swelling but did not protect the collapse of supporting structures, outer hair cell loss, or auditory thresholds. In conclusion, the noise-induced increase in aspartate and glutamate release in the cochlea and the protective effect of NMDA antagonism suggest that these two neurotransmitters are involved in noise-induced hearing loss.     

Hearing impairment in TRPV4 knockout mice

Transient receptor potential channel vanilloid subfamily 4 (TRPV4), a member of TRP family, is a mechanosensitive non-selective cation channel. To investigate the role of TRPV4 in the cochlea, the hearing thresholds and effects of acoustic overexposure on the cochlea were examined in TRPV4 knockout mice. TRPV4 knockout mice at age 8 weeks exhibited normal, but those at 24 weeks revealed significantly higher thresholds by auditory brainstem response. The auditory threshold shift was significantly larger in the TRPV4 knockout than in the TRPV4+/+ mice 1 week after the acoustic overexposure of 128dB SPL. The present findings suggest that disruption of TRPV4 causes delayed-onset hearing loss and makes the cochlea vulnerable to acoustic injury.