外源性谷氨酸对内耳毛细胞及听阈的影响  

Influence of exogenous glutamic acid on cochlea inner ear hair cells and hearing threshold

作　　者：屈涓[1] 刘顺利[1] 邱建华[1] 王锦玲[1] 邱淑萍[1] 

机构地区：[1]第四军医大学西京医院全军耳鼻咽喉专科中心,陕西西安710033

出　　处：《第四军医大学学报》2004年第6期560-563,共4页Journal of the Fourth Military Medical University

摘　　要：目的 :观察外源性谷氨酸对内耳毛细胞及听阈的影响 .方法 :将成年豚鼠随机分为 3组 ,经耳蜗钻孔分别给予谷氨酸 (Glu) (5 ,1 0 ,2 0mmol/L) .左耳为给药耳 ,右耳为对照耳 ,采用听觉脑干诱发电位 (ABR)、畸变产物耳声发射 (DP OAE)、耳蜗铺片、硝酸银染色及透射电镜技术 ,观察Glu处理前后不同时间的听力学、形态学改变 .结果 :术耳给药后 ,1kHzABR平均阈值分别为 (2 5 .0± 3.4 ) ,(33.9± 2 .7) ,(32 .2±4 .2 )dB ,8kHz分别为 (2 8.9± 3.7) ,(38.3± 2 .8) ,(37.8± 3.8)dB ,与对侧耳相比有显著差异 (P <0 .0 5 ) .耳声发射示 :给予低浓度Glu,图形在本底噪声之上 .随浓度的加大 ,耳声发射不能引出 .形态学改变 :耳蜗注入低浓度Glu时 ,外毛细胞(外 3排 )有轻微的错乱 ,内毛细胞较连贯 .随浓度的加大 ,外毛细胞三排都有较明显的改变 ,出现错乱、缺失 .内毛细胞出现缺失 ,形态改变 .与听力学变化一致 .结论AIM: To observe the influence of exogenous glutamic acid on inner ear hair cells and the hearing threshold. METHODS: 24 adult guinea pigs were divided randomly into three groups and given Glu (5 mmol/L, 10 mmol/L, 20 mmol/L), respectively through the holes drilled into the scala tympani of cochlea. The left ears were taken as the treatment ones and the right as the control ones. The changes in the audiology and morphology at different periods before and after giving the drug were observed by applying the technologies of auditory brainstem response (ABR), distortion product otoacoustic emission (DPOAE), cochlear preparation, silver nitrate dying and transmission electron microscope. RESULTS: After giving the drug to the operated ears, the average threshold level of ABR at 1KHz was (25.0±3.4 dB), (33. 9±2.7 dB) and (32.2±4.2 dB), respectively, and that at 8 KHz was (28.9±3.7 dB), (38.3±2.8 dB) and (37.8±3.8 dB), respectively ( P <0.05). The sharp differences were observed in comparison with the control ears. The DPOAE showed that after giving Glu of low concentration, the signals were above the background noise. The concentration above 5 mmol/L could not evoke DPOAE signals. When Glu of low concentration was injected into the cochlear scala tympani, there was a slight disorder of the outer hair cells (OHCs), but the inner hair cells (IHCs) were comparatively consistent in morphology. With the increase of Glu concentration, there were obvious changes in morphology and absence in three rows of the OHCs. The similar morphological changes occurred in IHCs, which corresponded with the changes of audiology. CONCLUSION: Glu probably has some toxic effects on inner ear hair cells.

关 键 词：谷氨酸/毒性 毛细胞 听阈 

分 类 号：R764.5[医药卫生—耳鼻咽喉科]