增龄对年龄相关性听力减退大鼠听觉神经通路形态学的影响

目的 探讨年龄相关性听力减退大鼠听觉神经通路组织形态随增龄的变化.方法 通过乙酰胆碱酯酶染色耳蜗基底膜铺片,蜗核、听皮层石蜡切片甲苯胺兰染色,比较3月龄和18月龄大鼠耳蜗底回的传出神经末梢数,蜗核、听皮层的神经元数量.结果 18月龄大鼠耳蜗底回传出神经末梢较3月龄大鼠减少36%(P＜0.0 1),缺失以2、3排外毛细胞为主;蜗核神经元减少24%(P＜0.01);但听皮层神经元两组之间无显著差异(P＞0.05).结论 年龄相关性听力减退大鼠听觉神经通路随增龄而退变.     

扩展高频测听对代谢综合征患者听觉功能早期损害的测试

目的探讨代谢综合征（MS）患者听觉功能早期损害的听力学特征,为研究和防治耳聋提供临床资料。方法选择20-50岁纯音听阈正常的健康者120例（240耳）作为对照组,同等年龄、纯音听阈正常并确诊为MS的患者130例（260耳）作为实验组,每耳在同一测试条件下行扩展高频测听。所得结果进行组间比较。结果同一年龄段实验组扩展高频测听阈值较对照组升高,20-40岁患者12kHz及以上频率阈值增高有显著意义（P〈0.05）。41-50岁年龄组10-14kHz频率阈值增高有显著意义（P〈0.05）,16kHz频率检出率下降有显著意义（P〈0.05）。结论MS是致聋的病因之一,也是加重老年性聋的因素,扩展高频测听可以在早期检测出MS患者的听力损害。     

The combined effect of cisplatin and furosemide on hearing function in guinea pigs

The effect of the combined administration of cisplatin and furosemide on the electrophysiological hearing thresholds and endocochlear DC potential (EP) was studied in guinea pigs. A lack of interaction was found in animals given repeated intraperitoneal injections of a low dose of cisplatin with a pharmacological dose of furosemide. An ototoxic interaction occurred when a moderately high dose of cisplatin was administered intravenously at a time when the strial function was most affected by a very high dose of furosemide. The interaction was seen both as a decreased EP and a pronounced shift of auditory thresholds. It is concluded that the stria vascularis plays a role in the ototoxic mechanism of cisplatin.     

一氧化氮在豚鼠耳蜗作用的实验研究

为探讨ＮＯ在内耳的作用，采用外淋巴给药途径，观察一氧化氮气体（ＮＯ）、Ｌ－精氨酸、硝普钠及一氧化氮合酶（ＮＯＳ）拮抗剂Ｎ－甲基－Ｌ－精氨酸对耳蜗蜗内电位（ＥＰ）、复合动作电位（ＣＡＰ）及耳蜗微音器电位（ＣＭ）的影响。结果表明，Ｎ－甲基－Ｌ－精氨酸可以使ＥＰ减小５０％，ＣＡＰ振幅降低３３％及ＣＭ振幅略有降低，在此基础上，用Ｌ－精氨酸外淋巴灌流可以逆转Ｎ－甲基－Ｌ－精氨酸所致的改变。ＮＯ持续外淋巴缓释能使Ｎ－甲基－Ｌ－精氨酸导致的ＥＰ、ＣＡＰ及ＣＭ的改变恢复，并超过正常，随之出现快速下降。外淋巴灌流硝普钠后，ＥＰ、ＣＡＰ及ＣＭ短暂升高后逐渐下降，并维持在较低水平。ＣＡＰＮ１波及ＣＭ潜伏期的变化规律与其振幅的变化规律基本一致。结果提示，ＮＯ在生理条件下维持内耳功能，可能参与耳蜗毛细胞微机械特性及敏感性的调节，过量表达可以产生耳蜗毒性     

先天性自身免疫性感音神经性聋防治的实验研究

目的 探讨免疫抑制剂环磷酰胺是否可以有效地预防和治疗先天性自身免疫性感音神经性聋.方法 同种粗制内耳抗原免疫雌性豚鼠,在妊娠期间给予免疫抑制剂环磷酰胺预防,对于未给予免疫抑制的母鼠所产子鼠给予环磷酰胺治疗,观察实验动物内耳听觉功能和病理形态学变化.结果 同时给予免疫抑制的母鼠及其各自所产子鼠均未出现明显的听觉损伤和内耳病理改变;出现听觉功能障碍和内耳病理变化的子鼠经环磷酰胺治疗后,其听觉功能有所提高(主要为低频区).结论 环磷酰胺可有效地预防母体内针对内耳组织特异性自身免疫反应所造成的子鼠先天性感音神经性聋,但疗效有限.     

一氧化氮在豚鼠耳蜗作用的实验研究

为探讨ＮＯ在内耳的作用，采用外淋巴给药途径，观察一氧化氮气体（ＮＯ）、Ｌ－精氨酸、硝普钠及一氧化氮合酶（ＮＯＳ）拮抗剂Ｎ－甲基－Ｌ－精氨酸对耳蜗蜗内电位（ＥＰ）、复合动作电位（ＣＡＰ）及耳蜗微音器电位（ＣＭ）的影响。结果表明，Ｎ－甲基－Ｌ－精氨酸可以使ＥＰ减小５０％，ＣＡＰ振幅降低３３％及ＣＭ振幅略有降低，在此基础上，用Ｌ－精氨酸外淋巴灌流可以逆转Ｎ－甲基－Ｌ－精氨酸所致的改变。ＮＯ持外淋巴缓释能     

多巴胺对豚鼠噪声性听力损失的保护作用

目的观察白噪声条件下多巴胺（dopamine,DA）对耳蜗内毛细胞的保护作用,为进一步探讨多巴胺对耳蜗传入通路的负反馈保护机制奠定基础。方法健康杂色豚鼠40只,随机分4组,行活体全耳蜗灌流：①单纯给予100dB白噪声组（以下同）;②灌流人工外淋巴液组;③灌流人工外淋巴液并给予白噪声组;④灌流1mmol/L多巴胺并给予白噪声组。在灌流第0、2h记录4kHz耳蜗微音电位（cochlear mirophonics,CM）幅值,并做相对幅度输入/输出函数曲线,和不同频率复合动作电位（compound action potential,CAP）阈值。结果给予噪声暴露的3组灌流后CM输入/输出曲线非线性特点均消失,相对幅度下降,差异有统计学意义（P〈0.05）。给予噪声暴露的3组2小时后各频率CAP阈值较前均上升,差异有统计学意义（P〈0.001）。但第4组较第1组除8kHzCAP阈移差异无统计学意义外,其余各频率CAP阈移明显减小（P〈0.05）。高频的阈移相差程度均较低频明显,其中16kHz阈移相差程度最为明显。结论白噪声暴露下多巴胺对耳蜗传入通路具有保护作用,并存在频率选择性,对高频纤维保护作用较低频更强。     

The Preyer reflex--an easy estimate of hearing function in guinea pigs

Preyer reflex thresholds elicited monaurally by tone bursts from 0.25 to 8 kHz were determined in more than 150 guinea pig ears. Normal reflex thresholds were between 85 and 95 dB SPL in the low and middle frequencies, decreasing to 75 dB in the higher frequencies. The range of measurements at single frequencies usually did not exceed 10 dB. In unselected populations of adult guinea pigs, about half of the animals had increased reflex thresholds--at least unilaterally, in most cases due to middle ear infections. The Preyer reflex showed parallel threshold increase with compound action potential thresholds in conductive loss and recruitment in cochlear hearing loss. Normal Preyer reflex thresholds do not necessarily mean normal hearing, but increased thresholds do indicate hearing impairment. This technique is valuable in the selection and monitoring of animals for otologic experiments.     

紫杉醇对豚鼠听阈的影响

目的：探讨紫杉醇对豚鼠听阈的影响。方法：将30只雌性豚鼠随机分为6组（1个对照组和5个实验组,每组5只）,实验组分别予以不同剂量紫杉醇腹腔内注射,检测用药前、后各组动物ABR阈值。结果：实验组听力水平用药后均显著减低,相关分析显示,总药量与听力损失程度之间无显著相关性。结论：紫杉醇可导致轻到中度听力损失。     

Effects of X-ray irradiation on hearing in guinea pigs

Effects of X-ray irradiation on the hearing with CM and ABR to both air- and bone-conduction stimuli were studied continuously from immediately after the irradiation to a few weeks later. At 2, 4, and 6 krad, only slight conductive hearing impairment was found, but at 8 krad or more, CM and ABR disappeared abruptly, after having increased briefly. Advanced sensorineural hearing loss appeared at about 10 hours after irradiation ended at 8 krad, at about 6 hours at 10 krad, and at about 3 hours at 12 krad. More severe hearing impairment was observed at higher frequencies and the endocochlear d.c. potential (EP) decreased at about 7 hours after 10 krad irradiation. Histologically, no discernible changes in the hair cells or sensory hairs were found with a scanning electron microscope at about 6 hours after 10 krad irradiation, while with a transmission electron microscope, the outer hair cells in the basal coil of the cochlea were found to be mostly destroyed. However, no changes could be found in the inner hair cells or other supporting cells.