摘要
目的观察外源性谷氨酰胺合成酶对噪声暴露引起豚鼠听力损失的保护作用。方法应用豚鼠全耳蜗灌流技术,右耳耳蜗灌流人工外淋巴液和不同浓度的谷氨酰胺合成酶2小时,同时持续性给予右耳白噪声2小时,分别记录噪声暴露前和噪声暴露后的耳蜗微音电位(CM);并且应用透射电镜技术观察噪声暴露前后耳蜗形态学的变化。结果全耳蜗灌流人工外淋巴液同时给予100 dB SPL的白噪声2小时,CM幅度显著下降,并且其非线性特点消失,复合动作电位(CAP)阈值为79．5 dB SPL;全耳蜗灌流0．5μ/L和1μ/L的谷氨酰胺合成酶同时给予100 dB SPL的白噪声2小时,CM幅度下降减轻,但CM的非线性特点仍不存在,CAP阈值升高,其中灌流1μ/L的谷氨酰胺合成酶时CM幅度和CAP阈值的恢复更明显。形态学显示1μ/L谷氨酰胺合成酶+噪声组内毛细胞及其下方传入神经纤维基本正常,但是外毛细胞仍存在空化。结论谷氨酰胺合成酶通过摄取噪声暴露时过度释放的谷氨酸,对噪声性听力损失有部分保护作用。
Objective To investigate the prophylactic effect of ectogenesis glutamine synthetase on noise-induced hearing loss in guinea pig. Methods During the whole cochlear infusion with noise exposure （white noise, 100 dB SPL）,the functional properties of the cochlear were measured by cochlear microphonics（CM） and compound action potential（CAP）; the morphology of the cochlear was monitored by transmission electron microscopy. Results The amplitude of CM was decreased and the nonlinear properties of CM I/O function became linearity. The average CAP threshold was elevated after noise exposure. Ectogenesis glutamine synthetase could reduce elevation in CAP threshold and decrease in CM amplitude induced by noise exposure. The protective effect of glutamine synthetase on noise-induced hearing loss was dose-dependent. TEM showed that the inner hair cells（IHCs） and afferent dendrites were normal, but there were still blebs in the outer hair cells（OHCs） of 1 μ /L glutamine synthetase in noise group. Conclusion The enzyme glutamine synthetase catalyses the conversion of glutamate to glutamine and has a partial protective effect on noise-induced hearing loss.
出处
《中国听力语言康复科学杂志》
2007年第4期16-19,共4页
Chinese Scientific Journal of Hearing and Speech Rehabilitation
基金
国家自然科学基金(项目编号39870797)
关键词
谷氨酰胺合成酶
耳蜗电位
噪声性聋
Glutamine synthetase
Cochlear microphonics
Noise-induced hearing loss
