丹参注射液对豚鼠耳蜗毛细胞的影响

目的观察丹参注射液对豚鼠庆大霉素耳中毒引起的耳蜗毛细胞酸性磷酸酶变化的影响。方法选用耳廓反射正常,体重250g～300g的健康杂色豚鼠,雌雄不限,随机分成3组,正常对照组15只,肌肉注射生理盐水2ml/(kg·d);庆大霉素组15只,肌肉注射庆大霉寨80mg／(kg·d);丹参注射液组15只,腹腔注射丹参注射液6mg／(kg·d),然后肌肉注射庆大霉素同庆大霉素组。各组动物连续注射药物均20天。用脑干听觉诱发电位(auditory brainstem response audiometry,ABR)检查豚鼠的听阈变化情况;用组织化学方法检测耳蜗毛细胞酸性磷酸酶的变化情况。结果正常对照组、庆大霉素组和丹参注射液组动物的ABR阈值分别为：(34.50±1.22)dB peSPL、(34.25±1.18)dBpeSPL和(34.39±1.27)dB peSPL;用药后第22天,反应阈值分别为：(34.65±1.32)dB peSPL、(71.25±24.73)dB peSPL和(41.05±10.93)dB peSPL。对照组分别与庆大霉素、丹参注射液组比较,差异显著(t=8.097,3.184,P＜0.01);丹参注射液组与庆大霉察组比较,有显著性差异(t=6.118,P＞0.01)。耳蜗铺片光镜下观察毛细胞酸性磷酸酶染色：正常对照组呈棕褐色,显色分布均匀,毛细胞排列整齐;庆大霉素组毛细胞依动物耳聋程度不同而出现不同程度染色缺失,庆大霉素组染色缺失显著,丹参注射液组染色缺失轻,两组比较有明显差异。结论丹参注射液能明显降低庆大霉素的耳毒性;保护耳蜗毛细胞溶酶体的完整性,降低庆大霉素对溶酶体的损坏而造成的毛细胞自溶性损伤,是丹参注射液降低庆大霉索耳毒性的机制之一。     

西地那非对豚鼠噪声性听觉损伤阈移的影响

目的 探讨西地那非(sildenafil)对豚鼠噪声性听觉损伤阈移的影响.方法 将豚鼠按随机数字表法分为对照组、噪声暴露组和西地那非给药组,每组10只.西地那非组及噪声组豚鼠在白噪声(A计权声压级110 dB)暴露1周后分别腹腔注射西地那非10 mg/(kg·d)及生理盐水4mL/(kg·d),连续给药4周.分别测试噪声暴露前1日、噪声暴露后1、2及4周听性脑干反应(ABR)阈值,并通过扫描电镜观察噪声暴露后4周豚鼠耳蜗毛细胞的形态变化.结果 噪声暴露1后,噪声暴露组豚鼠ABR阈值(声压级)平均提高19.1 dB,随着时间推移,阈移逐渐加大,暴露后4周,阈值平均提高22.0 dB;西地那非组噪声暴露后ABR阈值提高19.8 dB,给药后阈移逐渐减小,给药后4周,阈值仅平均提高4.8 dB.西地那非组与噪声暴露组相比,除噪声暴露结束后这一时间点以外,其余给药后各时间点ABR阈值差异均具有统计学意义(P值均＜0.05).扫描电镜显示,噪声组豚鼠耳蜗内、外毛细胞均出现听毛紊乱、融合及缺失;而西地那非组耳蜗病变较轻,听毛仅有轻微倒伏、融合现象.结论 西地那非能够减轻噪声对豚鼠耳蜗毛细胞的损害,降低噪声性听觉损伤引起的ABR阈值升高.     

耳蜗外毛细胞静纤毛束变异的判定标准与抵抗耳中毒的能力

目的建立耳蜗外毛细胞(OHC)静纤毛束变异的判定标准,观察毛细胞静纤毛束变异对庆大霉素耳中毒的抵抗能力.方法对豚鼠测定听性脑干反应(ABR)阈值和畸变产物耳声发射(DPOAE)振幅后,选取静纤毛束正常和变异豚鼠各5只,连续肌注庆大霉素(grntamicin,GM)12 d后,测定ABR阈值,扫描电镜观察耳蜗外毛细胞静纤毛束变异情况,耳蜗铺片计数毛细胞的损失数.结果耳蜗底回第一排外毛细胞静纤毛束转位超过45°、"W"变形数超过10%,作为豚鼠耳蜗外毛细胞静纤毛束变异的判定标准.5只静纤毛变异豚鼠GM注射12 d后平均ABR阈值51.0±8.76 dB SPL,外毛细胞损失约16%～39.96%,柯替器受损程度较轻;而外毛细胞(OHC)正常豚鼠GM注射12 d后ABR阈值上升到58.4～100 dB SPL,OHC基本消失,柯替器毛细胞破坏较为严重.结论耳蜗外毛细胞静纤毛束变异豚鼠较OHC正常者对GM中毒具有较大的耐受能力.     

水杨酸钠对噪声性听力损失影响的实验观察

目的　观察水杨酸钠能否减轻噪声引起的听力损失。方法　将 3 6只健康且耳廓反射正常的花色豚鼠随机分为水杨酸钠实验组、生理盐水对照组、水杨酸钠对照组和噪声暴露组。噪声暴露采用 10 5dBSPL的 4kHz窄带噪声下暴露 2h ,连续 5d。水杨酸钠给药为每天 0 5g/kg体重连续10d。由短声诱发听性脑干反应 (auditorybrainstemresponse ,ABR) ,连续测试其阈值 ;而后取动物双侧耳蜗荧光染色后光镜下行毛细胞计数和形态学观察。结果　ABR阈值测试显示 ,实验组动物在噪声暴露结束后 2 4h的听力略好于对照组 ;形态学观察表明 ,实验组细胞核异常数据低于对照组。结论　水杨酸钠可能在一定程度上具有拮抗噪声引起的听力损失及保护耳蜗毛细胞的作用     

天麻素对噪声性耳蜗损伤防护作用的实验研究

目的观察天麻提取液-天麻素对噪声性耳蜗损伤的防护作用.方法豚鼠28只随机分成3组,正常组8只、噪声组10只和天麻素组10只,暴露于噪声的同时加用天麻素.所有豚鼠均作ABR、耳蜗基底膜铺片和扫描电镜观察.结果噪声组(64.37dB)和天麻素组(31.25dB)ABR阈值均显著高于正常组(20dB),但天麻素组显著低于噪声组(P＜0.01).天麻素组耳蜗毛细胞和静纤毛损害均轻于噪声组.结论天麻素能降低豚鼠噪声暴露后的ABR阈值,减轻毛细胞损害,对噪声性耳蜗损伤有防护作用.     

5-磷酸二酯酶抑制剂对噪声性聋影响的实验研究

目的探讨5-磷酸二酯酶(PDE5)抑制剂对豚鼠噪声性聋的影响。方法豚鼠随机数字表法分为对照组、噪声暴露组和西地那非给药组,每组15只。西地那非组及噪声组豚鼠在白噪声暴露1周后分别腹腔注射西地那非10mg/(kg.d)及生理盐水4 ml/(kg.d),连续给药4周。分别测试噪声暴露前1天、噪声暴露后1、2及4周听性脑干反应(ABR)阈值及80dB HL下ABRⅠ波潜伏期,并通过扫描电镜观察噪声暴露后4周豚鼠耳蜗毛细胞的形态变化。结果与噪声暴露前相比,西地那非组ABR阈值及Ⅰ波潜伏期均小于噪声组,差异具有统计学意义(P值均<0.01)。扫描电镜显示,噪声组豚鼠耳蜗内、外毛细胞均出现听毛紊乱、融合及缺失;而西地那非组耳蜗病变较轻,听毛仅有轻微倒伏、融合现象。结论西地那非能够减轻噪声对豚鼠耳蜗毛细胞的损害,降低噪声性听觉损伤引起的ABR阈值升高,缩短其引起的Ⅰ波潜伏期延长。     

聚天冬氨酸抑制庆大霉素致耳蜗自由基产生的实验研究

目的观察聚天冬氨酸(polyasparticacid,PAA)对庆大霉素(gentamicin,GM)致耳蜗组织氧自由基产生的影响,进一步探讨PAA对GM耳毒性拮抗作用机制.方法将88只豚鼠随机分为Ⅰ组-单用GM、Ⅱ组-PAA+GM、Ⅲ组-单用PAA、Ⅳ组-单用生理盐水,采用电子顺磁共振法(electronparamagneticresonancespectroscopy,EPR),直接探测在体给药1、5、10d后,豚鼠耳蜗组织羟自由基(OH-)的产生量;同时,记录ABR,用透射电镜观察耳蜗Corti器毛细胞溶酶体形态改变.结果①给药1dⅠ、Ⅱ组耳蜗组织EPR积分值有升高趋势;ABR阈值4组间差异无显著性(P>0.05);耳蜗Corti器毛细胞溶酶体形态无明显改变.②给药5dⅠ组耳蜗组织EPR积分值(37.74±4.10)较其他3组明显升高(P<0.01),给药10d4组间耳蜗组织EPR积分值差异无显著性(P>0.05);超微结构Ⅰ组耳蜗Corti器毛细胞皮板下溶酶体改变给药10d较给药5d更明显,可见溶酶体聚集数量增多,体积明显增大;Ⅰ组ABR阈值随用药时间延长而升高.结论PAA对GM致耳蜗组织氧自由基的产生有抑制作用,从而拮抗了GM所致溶酶体磷脂沉积病态及耳蜗毒性的发生.     

外源性谷氨酸引发的内耳毛细胞损伤与支持细胞GLAST表达的相关性研究

目的观察外源性谷氨酸引发的内耳毛细胞损伤与支持细胞谷氨酸转运体(glutamate-aspartate trans-porter,GLAST)表达的相关性。方法将30只成年健康豚鼠随机分为3组,每组10只,经耳蜗钻孔,第一组动物左耳为对照组,给予人工外淋巴液(对照组);第二组动物左耳给予20mmol/L谷氨酸(Glu组);第三组动物为正常组,不作特殊处理。采用听性脑干反应(ABR)测试、耳蜗铺片、硝酸银染色及免疫组织化学技术,观察Glu处理前后的听力学、形态学改变,以及引发的支持细胞GLAST的表达变化。结果给药后,三组豚鼠1kHz ABR平均阈值分别为8.00±2.68、18.00±3.50、8.00±2.58dB nHL;8kHz分别为10.00±3.33、27.00±4.22、7.50±2.64dB nHL;Glu组与对照组有显著差异(P<0.05)。形态学改变:给予20mmol/L谷氨酸3d后,外毛细胞有较明显改变,出现错乱、缺失,内毛细胞出现形态改变,与听力学变化一致。免疫组织化学:正常组GLAST在支持细胞有表达,给予Glu后GLAST强阳性表达。结论谷氨酸对豚鼠内耳毛细胞具有毒性作用,GLAST参与外源性谷氨酸的转运,并受细胞外谷氨酸浓度的调控。     

复方丹参抗耳蜗外毛细胞凋亡的实验观察

目的 探讨氨基甙类抗生素所致耳蜗外毛细胞凋亡与听力损害关系及复方丹参对其凋亡发生的影响。方法 对35只豚鼠行药物造模,测试ABR阈值,TUNEL技术观察耳蜗外毛细胞凋亡发生情况。结果 正常豚鼠耳蜗外毛细胞无凋亡发生,耳毒性药物应用1d,3d后耳蜗各转外毛细胞均可出现凋亡阳性染色,中药干预组动物耳蜗外毛细胞凋亡数目相对较少,此外,豚鼠ABR阈值皆无明显升高。结论 耳毒性药物可诱发耳蜗外毛细胞发生凋亡;复方丹参能够对抗凋亡发生;凋亡发生早期对豚鼠听力阈值无明显影响。     

谷胱苷肽治疗早期庆大霉素耳中毒实验观察

目的了解庆大霉素(GM)早期耳中毒后,应用谷胱苷肽(GSH)治疗能否改善听力。方法选听力正常豚鼠30只,随机分3组,观察组12只(肌注GM100mg.kg-1*d-1,一旦ABR阈移10dB以上立即停药观察),治疗组12只(按观察组用药,停药,停药后再用GSH5天),对照组6只(仅肌注等量盐水)。所有动物在用药前后均检测ABR之波Ⅲ反应阈。停药二周后处死作耳蜗铺片。结果观察组停用GM二周后复查ABR阈移继续增大(P＜0.01)。治疗组停用GM二周后无明显阈移(P＞0.05)。对照组则前后无变化。耳蜗毛细胞形态变化与功能变化基本一致。结论早期GM耳中毒一旦出现ABR阈移即使立即停药听力损害仍将继续加重;GSH能阻止在耳蜗内蓄积的GM对听力进一步损害。     

水杨酸盐预防庆大霉素耳毒性的试验研究

目的 探讨大剂量应用庆大霉素时,观察水杨酸钠是否仍有预防耳毒性的作用。方法 选33只健康雄性豚鼠。随机分为A(11只)、B(11只)、C(11只)三组。A组腹腔注射药物庆大霉素+水杨酸钠;B组腹腔注射庆大霉素;C组腹腔注射生理盐水。每组动物用药前、用药后第2、4、6、8、10天分别行双耳ABR的阈值测试。耳蜗铺片光镜下毛细胞记数,分别用SPSS软件进行统计学处理。结果 体重:A组体重平均增加10.2克,B组体重平均减少5.2克,对照组体重平均增加16.5克,A组与B组比较差异有显著性(P<0.01)。ABR检查:第10天A组平均阈值为43.15±6.96,较B组平均83.93±19.33有显著改善(P<0.01),A组与对照组比较无显著性差异(P>0.05)。毛细胞计数:A组比B组损伤毛细胞数减少有显著性差异(P<0.01),B组毛细胞损伤明显增加,与对照组相比有显著性差异,A组与对照组无显著性差异。结论 提示在临床上为了在短期内控制细菌感染采用大剂量的庆大霉素时,仍可用水杨酸来预防其耳毒性。     

Antioxidant treatment reduces blast-induced cochlear damage and hearing loss

Exposure to blast overpressure has become one of the hazards of both military and civilian life in many parts of the world due to war and terrorist activity. Auditory damage is one of the primary sequela of blast trauma, affecting immediate situational awareness and causing permanent hearing loss. Protecting against blast exposure is limited by the inability to anticipate the timing of these exposures, particularly those caused by terrorists. Therefore a therapeutic regimen is desirable that is able to ameliorate auditory damage when administered after a blast exposure has occurred. The purpose of this study was to determine if administration of a combination of antioxidants 2,4-disulfonyl α-phenyl tertiary butyl nitrone (HPN-07) and N-acetylcysteine (NAC) beginning 1 h after blast exposure could reduce both temporary and permanent hearing loss. To this end, a blast simulator was developed and the operational conditions established for exposing rats to blast overpressures comparable to those encountered in an open-field blast of 14 pounds per square inch (psi). This blast model produced reproducible blast overpressures that resulted in physiological and physical damage to the auditory system that was proportional to the number and amplitude of the blasts. After exposure to 3 consecutive 14 psi blasts 100% of anesthetized rats had permanent hearing loss as determined at 21 days post exposure by auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE) testing. Animals treated with HPN-07 and NAC after blast exposure showed a significant reduction in ABR threshold shifts and DPOAE level shifts at 2-16 kHz with significant reduction in inner hair cell (IHC) and outer hair cell (OHC) loss across the 5-36 kHz region of the cochlea compared with control animals. The time course of changes in the auditory system was documented at 3 h, 24 h, 7 day and 21 day after blast exposure. At 3 h after blast exposure the auditory brainstem response (ABR) threshold shifts were elevated by 60 dB in both treated and control groups. A partial recovery of to 35 dB was observed at 24 h in the controls, indicative of a temporary threshold shift (TTS) and there was essentially no further recovery by 21 days representing a permanent threshold shift (PTS) of about 30 dB. Antioxidant treatment increased the amount of both TTS and PTS recovery relative to controls by 10 and 20 dB respectively. Distortion product otoacoustic emission (DPOAE) reached a maximum level shift of 25-30 dB measured in both control and treated groups at 3 h after blast exposure. These levels did not change by day 21 in the control group but in the treatment group the level shifts began to decline at 24 h until by day 21 they were 10-20 dB below that of the controls. Loss of cochlear hair cells measured at 21 day after blast exposure was mostly in the outer hair cells (OHC) and broadly distributed across the basilar membrane, consistent with the distribution of loss of frequency responses as measured by ABR and DPOAE analysis and typical of blast-induced damage. OHC loss progressively increased after blast exposure reaching an average loss of 32% in the control group and 10% in the treated group at 21 days. These findings provide the first evidence that a combination of antioxidants, HPN-07 and NAC, can both enhance TTS recovery and prevent PTS by reducing damage to the mechanical and neural components of the auditory system when administered shortly after blast exposure.     

模拟失重及飞船内稳态噪声对大鼠听功能的影响

目的 探讨模拟失重及飞船舱内中等强度稳态噪声对大鼠听功能影响的时效关系.方法 96只雄性SD大鼠随机分为失重组、噪声组、失重+噪声组和对照组,各24只鼠,每组大鼠再按暴露时间随机分为1周、4周组,各12只鼠,最后在暴露结束后即刻(P0)测听并处死一半大鼠作为暴露即刻组,另一半脱离暴露环境7d后(P7)测听并处死作为恢复...     

水杨酸钠中耳灌注对庆大霉素耳毒性的防护作用

目的 观察水杨酸钠经中耳局部灌注给药对庆大霉素耳毒性的防护作用。方法 24只健康杂色豚鼠均接受圆窗置管术，然后随机分成3组：Ⅰ组为生理盐水对照组；Ⅱ组为庆大霉素组，腹腔注射庆大霉素，经听泡灌注生理盐水；Ⅲ组为庆大霉素加水杨酸钠组，腹腔注射庆大霉素，经听泡灌注水杨酸钠。观察各组给药前后听性脑干反应阈的变化和给药后4周毛细胞损失情况。结果 听泡置管术后ABR反应阈无明显改变；给药后2周和4周，庆大霉素组ABR反应阈较庆大霉素加水杨酸组显著增高（P〈0．01），对照组ABR反应阈无显著变化。耳蜗铺片、毛细胞计数显示庆大霉素组外毛细胞严重缺失，以底回最明显，庆大霉素加水杨酸钠组外毛细胞损失较庆大霉素组轻（P〈0．05）。对照组无明显外毛细胞缺失。结论 水杨酸钠经中耳局部给药途径可减轻庆大霉素所致听功能损害和毛细胞缺失，可在一定程度上有效预防庆大霉素的耳毒性。     

二甲基亚砜对在体耳蜗毛细胞的毒性作用

目的研究二甲基亚砜(DMSO)对在体耳蜗毛细胞的毒性作用。方法取清洁级健康、ABR阈值正常SD大鼠32只,雌雄不限,体重100-120g。随机分成4组,人工外淋巴液对照组(即0%组)8只;0.1%DMSO溶液组8只;1%DMSO溶液组8只;5%DMSO溶液组8只。所有动物均取右耳作为实验耳。通过耳蜗鼓阶打孔显微注射向每个实验耳注入不同浓度DMSO溶液4ul。术前1天和术后7天分别进行ABR(click和toneburst)检测。激光共聚焦显微镜观察DMSO溶液导入7天后的毛细胞变化。结果人工外淋巴液对照组click、4kHz、8kHz、16kHz处阈移平均值均<5dBSPL,仅于32kHz处有约13dBSPL的阈移,形态方面未见明显损伤;0.1%浓度组在click、4kHz、8kHz处阈移平均值均<5dBSPL,而32kHz处阈移约25dBSPL,与人工外淋巴液对照组比较提示有统计学意义,激光共聚焦显微镜观察底回时偶见少数内毛细胞胀大;1%浓度即可引起OHC大量丢失,造成相应纤毛表皮板缺如,且以底回最重,各频率ABR阈移均>15dBSPL,32kHz处阈移>30dBSPL;当浓度增加到5%时,不仅损伤耳蜗底回的外毛细胞,也导致内毛细胞的丢失,所造成的听力损失在32kHz处较1%组严重。结论 DMSO对毛细胞的损伤存在剂量依赖性,损伤程度自耳蜗底回向顶回逐渐减轻。     

水杨酸钠对噪声性听力损失影响的实验

目的 观察水杨酸钠能否减轻噪声引起的听力损失。方法 将３６只健康且耳廓反射正常的花色豚鼠随机分为水杨酸钠实验组、生理盐水对照组、水杨酸钠对照组和噪声暴露组。噪声暴露采用１０５ｄＢ ＳＰＬ的４ＫＨｚ窄带噪声下暴露２ｈ,连续５ｄ。水杨酸钠给药为每天０．５ｇ／ｋｇ体重连续１０ｄ。由短声诱发听性脑干反应（ａｕｄｉｔｏｒｙ ｂｒａｉｎｓｔｅｍ ｒｅｓｐｏｎｓｅ,ＡＢＲ）,连续测试其阈值;而后取动物双侧耳蜗荧     

对乙酰氨基酚致小鼠听觉损伤的实验研究

目的：研究对乙酰氨基酚对小鼠听觉的影响。方法：健康7周龄C57小鼠40只，雌雄不分，随机分为4组：对乙酰氨基酚低剂量组（150mg／kg）、中剂量组（300mg／kg）、高剂量组（600mg／kg）及空白对照组（2ml生理盐水）。每组10只。观察每组于喂药第0、2、4、9天ABR反应阈，通过免疫荧光法观测耳蜗基膜毛细胞形态学改变，用高效液相色谱法测定小鼠耳蜗内淋巴液中对乙酰氨基酚浓度。结果：对乙酰氨基酚灌胃30min后，检测小鼠耳蜗内淋巴中对乙酰氨基酚的浓度，内淋巴中药物浓度与灌服剂量相关。对乙酰氨基酚各组随给药时间延长ABR听阈增高，中、高剂量组给药后9d的平均阈值分别为（44．75±16）dB、（50．00±11．00）dB，与对照组比较差异均有统计学意义（均P〈0．05）；随着灌服时间的延长，对乙酰氨基酚各组的免疫荧光镜显示内、外毛细胞出现不同程度的缺失。结论：对乙酰氨基酚可通过血迷路屏障进入内耳，服用一定剂量的对乙酰氨基酚可造成小鼠听力损伤。     

Effects of salicylate on electrically evoked otoacoustic emissions in the guinea pig

Clinically, salicylates have been known to have a ototoxic side effect of reversible hearing loss and to reduce the voltage-dependent length change (electromotility) in experiments on isolated outer hair cells (OHC). In order to clarify how the reduction of OHC electromotility due to salicylates contributes to cochlear dysfunction in vivo, we observed compound action potentials (CAP) threshold as well as the outputs of the electrically evoked otoacoustic emissions (EEOAE) before and after intravenous administration of 500 mg/kg sodium salicylate in a guinea pig model. A silver ball electrode placed on the round window membrane of the animal was used for both recording of the CAP and stimulation to elicit the EEOAE. The CAP threshold to tone bursts with frequencies from 2 to 10 kHz elevated by 13 to 22 dB, and outputs of the EEOAE decreased approximately 4 dB for 5 kHz stimulation, and 12 dB for 8 kHz after salicylate administration. These results suggested that systemically administered salicylate also reduced the electromotility of the OHC, and caused the hearing impairment in vivo.     

cis-diamminedichloroplatinum cochlear toxicity

Twenty-nine guinea pigs were divided into three groups. The first group received distilled water 2 ml/kg ip daily; the second group received DDP 2 mg/kg ip daily; and the third group DDP 4 mg/kg ip daily. ABR hearing threshold was tested before injection. Twenty-four hours after systemic administration, ABR hearing threshold was tested again. The animals were killed and the cochlear specimens were observed under light, scanning and transmission electron microscopes. No abnormality regarding ABR hearing threshold and cochlear morphology was observed in the first group. In the second group, ABR hearing threshold was elevated, inner and outer hair cells, supporting cells, striae vascularis and spiral ganglions were damaged. In the third group, ABR hearing threshold elevated markedly. All above-mentioned cells were severely damaged. The experiment showed that the cochlear damage induced by DDP was dose related. The severest damage was seen in the second turn of the cochlea. The damage to the Deiters' cells was earliest and severest. The outer hair cells were more vulnerable to the damage than the inner hair cells did.