FK506拮抗庆大霉素耳毒性的实验观察

目的 初步探讨FK506拮抗庆大霉素耳毒性的效果。方法 通过分别检测庆大霉素损伤组与庆大霉素加不同剂量FK506（1mg、2mg）保护组实验动物听性脑干反应(ABR)阈值的变化,并结合耳蜗铺片琥珀酸脱氢酶（SDH)染色方法观察动物耳蜗形态学变化,观察FK506拮抗庆大霉素耳毒性的作用。结果 实验动物的听觉生理检查显示FK506能够拮抗庆大霉素耳毒性,FK506保护组动物听阈明显低于庆大霉素损伤组(P<0.01),随剂量增加,保护作用越明显;同时形态结果显示FK506保护组外毛细胞缺失明显少于庆大霉素损伤组(P<0.01)。结论 FK506对庆大霉素引起的耳毒性有拮抗作用。     

应用畸变产物耳声发射观察褪黑素对庆大霉素耳毒性拮抗作用

目的 研究褪黑素（melatonin,MLT)对庆大霉素（gentamicin,GM)耳毒性的拮抗作用。方法 实验分为GM组，MTL＋GM组及生理盐水对照组，采用豚鼠畸变产物耳声发射（distortion product otoacoustic emission,DPOAE)，观察用药后DPOAE幅值及I／O曲线斜率的变化。结果 GM组用药3后，4，6，8kHz DPOAE幅值同对照组相比有显著性差异（P＜0．01）；I／O曲线斜率变小，在4，6，8kHz与对照组相比有显著性差异（P＜0．01）。GM＋MLT组用药后各频率段DPOAE幅值，与对照组相比地显著性差异；I／O曲线斜率无明显改变，同对照组相比无显著性差异（P＞0．05）。结论 MLT能有效拮抗庆大霉素的耳毒性作用。     

白藜芦醇拮抗庆大霉素耳毒性的实验研究

目的观察白黎芦醇（resveratrol,Res）对抗庆大霉素耳毒性的作用.方法将豚鼠随机分为庆大霉素（gentamicin, GM）组、白藜芦醇剂量I＋GM组 （ResI ）、白黎芦醇剂量II＋GM组（ResII）、白黎芦醇剂量III＋GM组（ResIII）及对照组.采用听性脑干反应（ABR）、耳蜗铺片及透射电镜技术,观察用药前后各组动物听阈及耳蜗毛细胞形态学改变,并检测血清丙二醛、超氧化物岐化酶含量、肾功能以及庆大霉素血药浓度.结果 ResIII组血液中丙二醛较GM组明显减少（P〈0.05）,GM＋Res各组超氧化物歧化酶活性均明显高于GM组（P〈0.05）,同时GM组1、8 kHz ABR 4 周平均阈移与ResIII剂量组间差异显著（P〈0.05）.形态学改变与听力变化一致.Res对庆大霉素血药浓度没有影响.结论大剂量Res能有效减轻GM的耳毒性作用,且不影响庆大霉素的抗菌作用.     

庆大霉素导致耳毒性中毒的自噬现象

目的庆大霉素是一种临床上常用的氨基糖苷类抗生素,随着其使用剂量和作用时间的增加,它的耳毒性逐渐明显。本实验在体外用新生C57BL/6J小鼠的耳蜗基底膜构建庆大霉素耳毒性模型观察自噬的发生。方法体外原代培养的耳蜗基底膜应用庆大霉素之后,行透射电镜观察自噬体的结构,免疫荧光、免疫印迹检测自噬相关蛋白LC3-II的变化。结果在庆大霉素的耳毒性模型中,观察到了自噬现象的发生。结论自噬参与了庆大霉素的耳毒性过程,提示我们干预自噬可以影响庆大霉素的耳毒性过程。     

庆大霉素耳毒性的临床调查

目的：调查临床使用庆大霉素所致听力损伤患者的发生率及特点。方法：平均使用庆大霉素1120mg，最长随访76天，采用纯音测听和听性脑干反应检查患者使用庆大霉素前后听力变化。结果：发生吸力损伤18例（26．5％），多数表现在高频区，且有4例为单耳损伤。一例有主观症状者治疗后耳聋减轻。结论：临床使用庆大霉素治疗期间及用药前后应了解听力情况和变化，并及时发现和处理听力损伤。     

聚DL—天冬氨酸对庆大霉素耳毒性拮抗作用的实验研究

目的 研究聚ＤＬ－天冬氨酸（ＰＡＡ）对Ｆ－３４４大鼠庆大霉素（ＧＭ）耳毒性的拮抗作用。方法 选用健康Ｆ－３４４大鼠５０只,随机分４组：Ｉ为ＧＭ、Ⅱ为ＰＡＡ＋ＧＭ、Ⅲ为ＰＡＡ、Ⅳ为生理盐水对照组;通过观测４组大鼠不同时期、不同频率听性脑干反应（ＡＢＲ）阈值的改变;计数耳蜗毛细胞死亡率,以观察ＰＡＡ对Ｆ－３４４大鼠ＧＭ耳蜗毒性的拮抗作用;用双向扩散血清培养基检测法观察ＰＡＡ对ＧＭ抗菌活性的影响。结果     

聚DL-天冬氨酸对庆大霉素耳毒性拮抗作用的实验研究

目的　研究聚ＤＬ天冬氨酸（ｐｏｌｙ ＤＬａｓｐａｒｔｉｃ ａｃｉｄ,ＰＡＡ） 对Ｆ３４４ 大鼠庆大霉素（ｇｅｎｔａｍｉｃｉｎ,ＧＭ） 耳毒性的拮抗作用。方法　选用健康Ｆ３４４ 大鼠５０ 只,随机分４ 组：Ⅰ为ＧＭ、Ⅱ为ＰＡＡ＋ ＧＭ、Ⅲ为ＰＡＡ、Ⅳ为生理盐水对照组;通过观测４ 组大鼠不同时期、不同频率听性脑干反应（ａｕｄｉｔｏｒｙ ｂｒａｉｎｓｔｅｍ ｒｅｓｐｏｎｓ,ＡＢＲ）阈值的改变;计数耳蜗毛细胞死亡率,以观察ＰＡＡ对Ｆ３４４ 大鼠ＧＭ 耳蜗毒性的拮抗作用;用双向扩散血清培养基检测法观察ＰＡＡ 对ＧＭ 抗菌活性的影响。结果　Ⅰ组短纯音１０ ｋＨｚ、８ ｋＨｚ ＡＢＲ阈值与其他３ 组差异有显著性（ Ｐ＜ ０．０１） ,给药１８ ｄ 耳蜗毛细胞死亡率与其他３ 组间差异也有显著性（ Ｐ＜０ ．０１）。结论　ＰＡＡ对庆大霉素的耳毒性具有拮抗作用,且不减低其抗菌活性。     

川芎嗪拮抗链霉素耳毒性作用及其离子通道机制

目的 研究川芎嗪（tetraethylplyrazine，TMP）拮抗链霉素耳毒性作用及其对耳蜗外毛细胞外向K^＋通道的影响，寻求两者的相关性，旨在探讨川芎嗪拮抗耳中毒作用的离子通道机制。方法 选取豚鼠60只，随机分为6组，即对照组、链霉素组、川芎嗪低浓度组、川芎嗪高浓度组、川芎嗪低浓度＋链霉素组和川芎嗪高浓度＋链霉素组，分别注射生理盐水（2．5ml/kg）、链霉素（450mg／kg）、川芎嗪（12mg／kg）、川芎嗪（60ms／ks）、川芎嗪（12mg／kg）＋链霉素（450mg／kg）、川芎嗪（60mg／kg）＋链霉素（450mg／kg），用药10天后检测各组豚鼠ABR反应阈，并采用全细胞膜片钳技术观察川芎嗪对耳蜗外毛细胞Ca^2＋敏感K^＋电流和延迟外向K^＋电流的影响。结果 结果表明川芎嗪明显降低链霉素所致的豚鼠ABR反应阈升高，提示川芎嗪具有明显的拮抗链霉素耳毒性作用；川芎嗪能明显增大豚鼠耳蜗外毛细胞Ca^2＋敏感K^＋电流和延迟外向K^＋电流，并呈浓度依赖关系。结论 川芎嗪可能通过增大K^＋通道电流而发挥其降低链霉素耳毒性作用，推测这是其抗耳毒性作用机制之一。     

耳毒性药物破坏前庭功能后产庭功能恢复的观察

随访应用庆大霉素及硫酸链霉素治疗严重梅尼埃病４７例的前庭功能状态。其中以庆在霉素鼓室２５例，２例分别于治疗后，５、７个月眩晕复发，以硫酸链霉素外半规管灌注１９例，２例分别于治疗５、６个月眩晕复发，以硫酸链霉素肌注３例，１例于治疗后１０个复查，发现前庭功能恢复。     

Comparison of the effects of lipoic acid and glutathione against cisplatin-induced ototoxicity in auditory cells

ObjectivesThe aims of this study were to examine lipoic acid (LA)- or glutathione (GSH)-mediated protection against cytotoxicity following cisplatin exposure in HEI-OC1 auditory cells and measure the potential of LA and GSH to scavenge reactive oxygen species (ROS). This study also compares their protective effects and discusses the determination of a preventive or therapeutic dose.MethodsHEI-OC1 cells were pretreated with LA or GSH for 24 h and then exposed to 15 μM cisplatin for 48 h. The resulting cytotoxicity was measured using a cell counting kit-8, and intracellular ROS level was measured using flow cytometry. The protective or anti-ROS effects of LA and GSH were compared. Measurement of caspase 3, 8, 9 activity and Western blot analysis of PARP were performed.ResultsPretreatment with LA at 300 μM and GSH at 3 mM protected HEI-OC1 cells against cisplatin-induced cytotoxicity and significantly reduced the cisplatin-induced increase in ROS. LA showed a significantly more effective protection against cisplatin-induced ototoxicity compared to that shown by GSH (85.4% vs. 73.1% cell viability). Both LA and GSH showed the maximal protective effect at different concentrations in normal or cisplatin-induced cytotoxic conditions. The preventive or therapeutic dose for harmful conditions is quite different for the two drugs and needs careful adjustments.ConclusionThis comparative study on the protective effects of LA and GSH against cisplatin-induced ototoxicity in an auditory cell line posed many challenges. Although LA and GSH showed a significant protective effect against cisplatin, the LA's effect was superior. The concentration at which the maximal protective effect of LA or GSH was noted was 3 times higher in cytotoxic conditions than in normal conditions, which suggests the need for drug dose adjustments based on the purpose (preventive or therapeutic).     

Transplacental kanamycin ototoxicity in the guinea pig

Summary The effect of kanamycin on the cochlear sensory epithelium of albino guinea pig fetuses was studied histologically following the administration of 200 or 400 mg/kg body weight kanamycin sulfate to the pregnant mothers for 8 consecutive days at different stages of gestation. Surface view analysis of Corti's organ revealed slight damage following treatment in the middle trimester of gestation and marked damage due to treatment in the last trimester. The pattern of hair cell loss induced during and after the functional differentiation of the cochlea resembled the pattern of ototoxic lesions in the adult ear. The assumed mechanisms for induction of teratogenesis by kanamycin in the fetal organ of Corti are discussed.Established investigator of the Chief Scientist's Bureau, Ministry of Health, Israel     

红目豚鼠与黑目豚鼠庆大霉素耳毒作用差异遗传特性

目的发现与线粒体DNA有关对氨基糖甙类抗生素耳毒作用敏感性不同的动物模型,从动物模型的建立探讨人类线粒体DNA突变与不同个体对氨基糖甙类抗生素耳毒作用敏感性不同的相关性.方法将纯种的红目豚鼠与黑目豚鼠进行杂交,子代给予肌注庆大霉素(110mg·kg-1·d-1)9天,用耳蜗电图和畸变产物耳声发射(DPOAE)等客观听阈检测指标观察子代豚鼠的听力,比较雌性红目豚鼠的后代和雌性黑目豚鼠后代对氨基糖甙类抗生素的敏感性.结果肌注庆大霉素第9天时,亲母代为白色、子代为白色豚鼠引出DPOAE率为8/9;亲母代为花色豚鼠、子代为白色豚鼠引出DPOAE率为4/11;亲母代为白色豚鼠、子代为花色豚鼠引出DPOAE率为6/6亲母代为花色豚鼠、子代为花色豚鼠引出DPOAE率为2/8.结论提示白色豚鼠和花色豚鼠对氨基糖甙类抗生素耳毒作用的敏感性的不同与核内的基因关联不大,可能与线粒体DNA有关,从而为确定何种动物中线粒体中有作用基因提供了实验依据.     

Specific glutathione-SH inhibition of toxic effects of metabolized gentamicin on isolated guinea pig hair cells

The present investigation has shown that only metabolized gentamicin (mG) but not native gentamicin (G) is cytotoxic for isolated guinea pig outer hair cells (OHC). Using FURA-2 fluorescence, both G and mG were found to reduce intracellular free Ca²⁺ concentrations in unstimulated OHC and inhibit increases in intracellular Ca²⁺ concentrations during K⁺-induced depolarization. Glutathione-SH (GSH), a detoxificating agent, did not interfere with G and mG effects on intracellular Ca²⁺ concentration. In non-stimulated OHC, mG but not G induced pathological OHC depolarization, indicating the opening of transduction channels to allow influx of K⁺ ions. GSH completely inhibited the lytic effect of mG. Electrophysiological investigations also revealed that GSH probably inhibits mG-induced pathological opening of transduction channels. These results suggest that GSH selectively inhibits mG-specific toxic effects on the guinea pig OHC, possibly by enzymatic detoxification.     

An immunohistochemical method for the study of aminoglycoside ototoxicity in the guinea pig cochlea using decalcified frozen sections

Summary An immunohistochemical technique with decalcified frozen sections was used to study aminoglycoside ototoxicity. Decalcified guinea pig cochleas were cut with a fine blade parallel to the plane of the modiolus to facilitate the penetration of inclusion material and the manipulation of frozen sections. Light microscopy was carried out and additional frozen sections were employed for an immuno-electron microscopic study. Twenty-four hours after a single transtympanic injection of 10 mg gentamicin, there was a definite distribution of the drug in only type I hair cells of the ampullae as well as in both inner and outer hair cells along the length of the cochlea. In those animals treated intraperitoneally with 200 mg/ kg amikacin for 8 days, the drug was located in the outer hair cells of the cochlea, with a tendency to decrease from base to apex and in the inner hair cells towards the apex.Read at the XVIIIth International Congress of Audiology, Prague, Czechoslovakia, 26 August 1986     

Relationship between the nephrotoxicity and ototoxicity induced by gentamicin in the guinea pig

Guinea pigs were treated with daily single subcutaneous injections of 60 mg gentamicin per kg for 3 weeks. Renal, cochlear and vestibular functions were monitored before, during and after treatment. The degree and onset of gentamicin oto- and nephrotoxocity differed during the treatment period. Alterations to the kidney functions were observed from the first week while the onset of ototoxicity occurred later, at the third and fourth week for the cochlear and vestibular functions respectively. Moreover, when treatment ended, renal function demonstrated signs of recovery, while auditory and vestibular function continued to worsen. Deficits in cochlear function and structural changes (missing outer hair cells) correlated with gentamicin serum concentrations, while vestibular alterations (loss in nystagmic reactions) did not. No distinct relationship could be established between auditory and vestibular loss and the renal parameters monitored. The results suggest that gentamicin-induced nephro- and oto-toxicity are dissociated phenomena and that cochleotoxicity was dependent on aminoglycoside serum level.     

Comparative ototoxicity of gentamicin in the guinea pig and two strains of rats

Gentamicin ototoxicity and nephrotoxicity were compared in two strains of rats, Sprague-Dawley and Fisher-344, and in the Hartley albino guinea pig. Treatment groups consisting of 8 male rats of each strain and four male guinea pigs were dosed subcutaneously for 14 days with either 80 or 100 mg/kg of gentamicin sulfate in saline. Brainstem auditory evoked response (BAER) thresholds were recorded from each animal in each group on day 11 post-administration. Blood urea-nitrogen and serum creatinine were measured in blood obtained on day 11 post-administration as measures of nephrotoxicity. Kidney weight/body weight ratios were also determined. Loss of sensory hair cells was observed in the basal region of the organ of Corti from all animals treated with 100 mg/kg of gentamicin. The hair cell loss and BAER threshold elevations were greatest in the guinea pigs. Fisher-344 rats showed more extensive hair loss and greater BAER threshold elevations than Sprague-Dawley rats. The Fisher-344 rats exhibited increased blood urea-nitrogen and kidney weight/body weight ratios. Sprague-Dawleys did not suffer any nephrotoxic effects. These data indicate that the Fisher-344 rat is useful animal in which to study aminoglycoside ototoxicity as it exhibits both functional and morphological changes after gentamicin administration.     

Endothelial nitric oxide synthase upregulation in the cochlea of the guinea pig after intratympanic gentamicin injection

Single-shot transtympanic gentamicin therapy has become a popular treatment modality for Menieres disease despite the known possible ototoxic properties of this drug. It was shown recently that NO production and iNOS were upregulated after gentamicin application, which was interpreted as a possible effect of ototoxicity. In this study we analyzed the expression of eNOS after gentamicin application to determine a possible correlation of this enzyme with gentamicin-induced ototoxicity. We compared eNOS expression in gentamicin-treated and non-treated guinea pigs in the second turn of the cochlea, an area corresponding to speech perception in humans. Gentamicin (4 mg) was injected intratympanically into the middle ear of guinea pigs ( n =3) and the reduction of the hearing threshold level was determined by recording acoustic-evoked potentials (AEP) before and 5 days after gentamicin application. Morphological alterations in the organ of Corti were analyzed by light and electron microscopy. Gold-labeled anti-eNOS antibodies were counted in eight different cell areas for quantification of eNOS expression. Seven animals were analyzed as controls. After gentamicin application, a deterioration of hearing level was observed varying from 10 to 30 dB. A high degree of vacuolization was identified in the third row of outer hair cells. At the subcellular level, the subsurface cisterns in outer hair cells were dissociated from the basolateral cell membrane, and the mitochondrial membranes were frequently damaged. Statistically significant upregulation of eNOS was observed in all cell types analyzed. Depending on the various cell types the amount of gold-labeled eNOS antibodies was 2.5 to 5.7 times higher after gentamicin application. We observed significant eNOS upregulation after gentamicin application in the cochlea, in conjunction with cellular damages and decreased hearing.     

庆大霉素慢性耳中毒对听觉和传出神经功能的影响

目的：探讨庆大霉素慢性耳中毒对听觉和传出神经功能的影响。方法：在庆大霉素应用前后通过观察对侧噪声（ＣＬＮ）对听神经复合动作电位（ＣＡＰ）的影响确定内侧橄榄耳蜗（ＭＯＣ）系统功能,通过测试在４,６,８,１０和１２ｋＨｚ的ＣＡＰ反应阈确定听功能。结果：注射庆大霉素后３周和１１周。ＣＬＮ对ＣＡＰ的抑制效应呈进行性、不可逆性消除,且以１１周最明显,ＣＡＰ反应阈分别上升１０和２５ｄＢ,与耳蜗传出神经和毛细胞