【作者】 陈浩；

【导师】 郭梦和；

【作者基本信息】 南方医科大学 ， 耳鼻咽喉科学， 2007， 硕士

【摘要】 感音神经性聋是耳鼻咽喉科常见病，据最新的第二次抽样调查，全国约有2004万耳聋病人。发病原因公认有缺血、病毒感染、耳毒性药物中毒及老年性退行性变等。病理改变主要是毛细胞损伤、螺旋神经节、支持细胞及神经末梢的器质性改变。相当多治疗效果不佳，并且至今没有很好的方法。药物治疗无效的患者只有配戴助听器或行人工耳蜗植入术。近年来一些研究报道了哺乳动物甚至人的内耳前庭及耳蜗毛细胞在受伤后可能再生。临床上可见到一些在庆大霉素治疗后双耳重度感音神经性聋患者，在停药三周后听力在低频区提高15-20dB，3个月后所有频率均有10-25dB的恢复。这些现象说明人类前庭和耳蜗功能的恢复与鸟类内耳毛细胞再生及功能恢复相一致的现象是可能存在的。同时，近几年许多研究证明，体外培养的耳蜗Corti器用生长因子类物质可促进内耳受损的神经和毛细胞修复再生。给耳聋治疗带来了极大的希望，但有关哺乳动物的在体试验尚未取得成功。胰岛素样生长因子(insulin-like growth factor，IGF)是一类广泛存在机体的多种器官和组织中的蛋白多肽，因其基因结构和胰岛素具有高度同源性，具有类似胰岛素的作用而得名。尤其以胰岛素样生长因子-1(insulin-like growthfactor-1，IGF-1)在有促进机体的生长发育、促进组织修复、促进物质及营养代谢、降低血糖和促进细胞分化分裂增殖等方面起着类似丝裂素及胰岛素样重要的生物学作用。IGF-1的生物学效应可通过自分泌和旁分泌来实现，通过靶细胞表面的特异性受体介导，是内耳正常发育中不可缺少的调节因子，可以调节听泡细胞的增殖、死亡和神经元的发育和分化。所以推测，IGF-1可以作为一种较有前途的，能促进内耳毛细胞再生和促进听神经修复，可以治疗毛细胞和听神经受损所致听力障碍的药物。内耳由于耳蜗的骨性结构及具有血-脑和血-迷路双重屏障的存在，使耳蜗成为一个相对封闭的微环境，可能使大多数蛋白类生长因子和神经营养药物难以有效充分的到达内耳，故给许多内耳疾病治疗带来了极大的困难。近年来，耳蜗鼓阶开窗便成为基因、细胞生长因子等导入耳蜗的重要途径。在开窗术的基础上，将开窗孔径控制在尽量不影响听力的范围内而产生了微孔技术。Stover等研究认为，经鼓阶钻孔及通过圆窗膜途径注射病毒载体对听力没有明显影响。我科现在已成功完成了150多例电子耳蜗植入术，电子耳蜗植入术实际上即是鼓阶开窗、微孔技术的应用，并进行电极的插入，对本项研究中有一定的借鉴作用。赵长青曾用耳蜗微孔技术行豚鼠耳蜗灌注进行诱发电位的研究，发现用耳蜗微孔技术进行内耳开窗，绝大多数听力损失在0-5dB，且1-2周内可恢复正常。高鹏飞等认为豚鼠鼓阶开窗(直径约为0.6mm)修复后对其听阈和听毛细胞无明显影响。所以我们通过耳蜗微孔技术将IGF-1注入耳蜗进行感音神经性聋的治疗，可以基本忽略手术本身对听力的影响。本实验为课题研究的动物实验部分，拟用庆大霉素制造感音神经性聋的动物模型，然后通过在豚鼠耳蜗底回开窗，微孔注IGF-1入鼓阶，来研究IGF-1对庆大霉素致耳聋豚鼠的治疗作用，为临床治疗研究提供实验依据。目的探讨通过鼓阶开窗，微孔技术注IGF-1入内耳，研究IGF-1对感音神经性聋动物模型(庆大霉素致耳聋豚鼠)的治疗作用。方法1．材料：选取健康杂色黑目豚鼠50只(二级、南方医科大学珠江医院实验动物中心提供)，体重为250-300g，雌雄不拘，耳廓反射灵敏，鼓膜完整、标志清楚，ABR检查排除听力异常者。2．实验步骤：试验主要分四部分进行：(1)将50只豚鼠按照随机化原则均分为两组：设A组(正常对照组，25只)、B组(庆大霉素致耳聋模型组，25只)。A组正常条件下饲养，B组肌注庆大霉素(GM)连续28天，用听性脑干诱发电位监测造模效果。(2)改进实验方法，研究清醒状态能否取代麻醉状态来进行豚鼠ABR测试，以降低豚鼠(尤其是庆大霉素致耳聋豚鼠)的意外死亡率，保证实验顺利进行。(3)造模完成后，将A组选20只随机均分为Ⅰ组(正常组，10只)，Ⅱ组(手术组，10只)；将Ⅰ组正常饲养，Ⅱ组行内耳鼓阶开窗，微孔注入术。了解手术对豚鼠听力及耳蜗组织结构的影响。(4)B组选20只随机均分Ⅲ组(GM组，10只)，Ⅳ组(IGF-1组，10只)。Ⅲ、Ⅳ组行内耳鼓阶开窗，Ⅲ组在鼓阶内注入人工外淋巴液、Ⅳ组微孔注入IGF-1。研究IGF-1对GM致聋豚鼠的治疗作用。每部分实验中，进行统计学分析(所有数据均由测听系统电脑记录，采用SPSS13.0软件包进行数据处理，用相应方法进行统计学分析)和形态学观察(利用光镜，扫描电镜，透射电镜进行形态学观察研究)。结果1．B组注射庆大霉素28天后与A组反应阈有显著差异(P＜0.01)。2．A组在清醒和麻醉状态下反应阈，Ⅰ、Ⅲ波间期无显著差异(P＞0.05)3．Ⅰ组和Ⅱ组反应阈在术后7天无显著差异(P＞0.05)。Ⅱ组反应阈在术前1小时和术后7天无显著差异(P＞0.05)。4．Ⅲ组和Ⅳ组反应阈在术后14天有显著差异(P＜0.01)。Ⅳ组反应阈在术前与术后14天比有显著差异(P＜0.01)。结论1、庆大霉素具有耳毒性，但肾毒性较其他氨基糖甙类抗生素小，价格便宜，临床应用广泛，较易获得，是制造感音神经性聋动物模型的理想药物。2、ABR测试具有波形稳定易辩，记录方便，从其波形的反应阈、各波潜伏期、波间期、振幅等可以分析听觉脑干通路及其附近结构的生理病理情况，是客观评价豚鼠听力变化的理想指标。3、由郭梦和教授研制的“听觉电生理动物实验平台”测听系统准确可靠，简便易行，适合动物实验测听需要。4、豚鼠ABR测试可在清醒状态进行，较以往麻醉后进行有以下优势：数据准确，操作简便，降低豚鼠死亡率，更接近豚鼠正常生理状态。5、内耳鼓阶开窗、微孔技术操作简便、安全，对听力没有显著影响，有望成为治疗耳聋及其他内耳疾病的有效方法。6、IGF-1对GM致聋豚鼠听力恢复具有一定的作用，其机理可能为促进毛细胞修复和神经再生。可做为治疗感音神经性耳聋的药物投入临床实验。更多还原

【Abstract】 Sensorineural hearing loss is one of common diseases inOtorhinolaryngology-Head and Neck Surgery; there are more than 20 million deafpatients in the nation. Lack of blood, virus infection, ototoxic deafness, anddegenerate pathological changes of ageness and so on are the public recognizedcauses of disease. Pathological changes are mainly result from hair cellsdamnification, organic changes in spiral ganglion, support cells and nervous twigs. Agood few of treatments do not get effectness, so till now it has no good method.Patients who are irresponsive to the medicine treatments can only get help with thehearing aid or do the cochlear implant.In recent years, some researches reported the internal vestibule and cochlear haircells of mammalians, even human, were possibly reproduced after injured. Somesensorineural hearing loss in both ears patients in clinic, after genetamicin treatment,improved the audition 15-20Db in low frequent distict after ceasing the medicine 3weeks, and improved 10-25Db in all frequent distict after 3 months. All the aboveproves that the functions of vestibules and cochlears of human could be possibly rebuilt as the hair cells of inner ears of birds do. At the same time, many researchesin recent years proved that using the growth-factor substance can boost the restoringand rebuilding of the harmed nerves and hair cells of inner ears in outside-bodycultivated cochlear Corti organs. The news brings galactic hope for the hearing losspatients, but the trials carried on mammalians are still failed.Insulin-like growth factor (IGF) is one kind of proteins abroadly existing inmany apparatuses and organs. IGF obtains the name because that its gene frame ishighly affinal with insulin, and also it has similar effect as insulin. Especially IGF-1has the same important biological effects as insulin in boost the growth of economy,the organic restoring, substance and nourition metabolization; promote thepolarization and split of cells and so on. Biological function of IGF-1 can carry outthrough autocrine and paracrine, as well through the special isomerism acceptor oftarget cell. IGF-1 is the indispensable accommodate factor during the normal growthof inner ears. It can accommodate multiplication or death of cochlear, growth andpolarization of nerve cells. So it is conjectured that IGF-1 can be used as apromising medicine to boost the rebuilding of hair cells and the restoring of acousticnerve, to cure heating obstacle.Cochlear becomes a comparative close micro-entironment, as the doubleobstacles exist in the inner ear—the bone frame of cochlea and blood-braid as wellas blood-labyrinth barriers. As a result, most of protein growth factors and nervenutrition medicines may hardly enter inner ear efficiently, bringing tremendousdifficulty in curing ear diseases. Recently, inner ear scala tympani Fenestration arethe main approach to lead the gene-growth factor, cell-growth factor and so on tothe inner ear. Base on Fenestration, to control the aperture of fenestration in thescope of not influencing audition is micro-aperture technique. After reseached,Stover believed that injecting virus holder through scala tympani drill and round window theca did not impact the audition. Our department has done more than 150cases of electronic cochlear transplantation, which is the application of scalatympani Fenestration and micro-aperture technique, and a useful reference for thisresearch. Zhao Changding studied the evoked potential using cochlearmicro-aperture techniqu, and found out most of the guinea pigs lossed 0-5dB, butgot normal within one to two weeks. Gao Pengfei believed the aperture of scalatympani fenestration was about 0.6 mm, and after restored, it did not have evidenceeffect on hearing threshold and hearing hair cells. So we can basically ignore theinfluence on the hearing of the surgery if injecting IGF-1 into inner ears throughcochlear micro-aperture technique to cure sensorineural deafness.ObjectiveStudy the treatment effect of IGF-1 for sensorineural deafness of animal mode(GM-induced hearing loss guinea pigs), by injecting IGF-1 into inner ears throughscala tympani fenestration and micro-aperture technique.Methods1. Materials50 healthy mottle and black-eyed guinea pigs (rank 2nd, provided by AnimalExperiment Center of Zhujiang Hospital, Southern Medical Universtiy), weightranging from 250 to 300g, of either gender, with sensentive auricles, entire tympanicmembrane, excluding abnormal hearing guinea pigs by ABR.2. Experiment Process:Three main processes:(1)50 guinea pigs were randomly divided into two groups: Group A (control group,25), Group B (GM-induced hearing loss guinea pigs, 25). Group A were fed undernormal condition, while guinea pigs of Group B were muscular injected GM for continuous four weeks and monitored by ABR.(2)Improve the research method, study guinea pigs ABR test consciousness instead ofnarcotism to reduce sudden death rate of guinea pigs (especially GM-induced hearingloss guinea pigs), ensure the success of study.(3) After built-up the mode, chose 20 guinea pigs from Group A, then divided intoGroupⅠ(normal group, 10) and GroupⅡ(surgery group, 10) randomly; GroupⅠwere fed under normal condition. GroupⅡwere conducted scala tympanifenestration, with a view to get known the affect on the hearing and cochlea organs ofguinea pigs.(4) Chose 20 guinea pigs from Group B, then divided into GroupⅢ(GM group, 10)and GroupⅣ(IGF-1 group, 10); GroupⅢand GroupⅣwere conducted scalatympani fenestration, GroupⅢwere injected article lymph, GroupⅣwere injectedIGF-1, to study the therapy effect of IGF-1 to GM-induced hearing loss guinea pigs.Each part was conducted Statistics analyszed (all datas were recorded by auditiontesting system, using SPSS13.0 to process datas and statistica analysed by reletivemethods) and Morphological observation (conduct morphological study through SEMand TEM).Results1.ABR RT has prominent difference (P＜0.01) between Group A (normal controlgroup) and Group B (GM-induced hearing loss group) which had been injected GMafter 28 days.2.It did not have prominent difference (P＞0.05) in ABR RT orⅠ,ⅢPL undernarcotism or consciousness of Group A (normal control group).3. ABR RT has no prominent difference (P＞0.05) between GroupⅠand GroupⅡ7days after surgery. ABR RT has no prominent difference (P＞0.05) in GroupⅡone hour before and 7 days after surgery.4. ABR RT has prominent difference (P＜0.01) between GroupⅢand GroupⅣ14days after surgery. ABR RT has prominent difference (P＜0.01) in GroupⅣbeforeand 14 days after surgery.Conclusion1. GM is ototoxic, but less kidney toxin compared to other AmAns, cheap price, wideuse in clinic, and easily obtained, an ideal medicine to conduct sensorineural deafnessof animal mode.2. ABR test is an ideal index to value the audition change of guinea pigs impersonally,owning to stable and easy to dispute wave, record conveniently, analyzing thepathology of auditory brainstem and nearby functions through RT, PL, IPL, AP and soother of wave.3. Hearing-test system developed by Professor Guo Menghe is excutitude andcredible, easy to conduct, so it meets the needs of animal audition test.4. ABR test of guinea pigs conducted under consciousness, has the followingadvantages compared to under under narcotism: accurate data, easy handle, reducingdeath rate of guinea pigs, and more closer to the normal condition of guinea pigs.5. Scala tympani fenestration and micro-aperture technique are easy handle and safe,not affect the function of cochlea, which are likely to be the effective treatment tohearing loss and other inner ears diseases.6. IGF-1 can promote and support the regeneration of hair cells of inner ears, whichcan be the medicine for sensorineural deafness, testing in clinic trials.更多还原