隐性听力下降小鼠耳蜗内毛细胞突触的病理改变

发布时间：2018-06-25 10:56

本文选题：噪声性聋 + 暂时性阈移　；参考：《复旦学报(医学版)》2017年02期

【摘要】：目的探讨噪声暴露后出现暂时性阈移的小鼠在听觉反应阈值完全恢复正常后耳蜗内毛细胞突触的病理改变。方法将小鼠分为正常对照组和实验组,实验组小鼠进行强度98 dB SPL、时长2 h的噪声暴露,建立暂时性阈移模型。将对照组和暂时性阈移模型小鼠进行全基底膜铺片并行免疫荧光染色,共聚焦显微镜拍照成像并观察细胞形态。利用耳蜗长度计算耳蜗所处的频率位置,最后用图形处理软件对突触结构进行三维重建,观察对照组小鼠和实验组小鼠的耳蜗内毛细胞突触前、后结构的空间分布规律及其病理改变特点。结果对照组小鼠耳蜗内毛细胞的突触复合体有明显的分布特点,每个内毛细胞通过5~30个突触与耳蜗神经纤维形成突触连接,靠近蜗轴侧的突触前结构体积较大,与之相匹配的突触后结构体积较小。靠近柱细胞侧的突触前结构体积偏小,与之相匹配的突触后结构体积偏大。实验组小鼠在高强度噪声暴露后第2天听觉测试结果显示,听性脑干反应(auditory brain-stem response,ABR)和畸变产物耳声发射(distortion product otoacoustic emission,DPOAE)阈值升高30~40 dB,2周后再次测试显示阈值恢复正常,但是ABR的Ⅰ波波幅下降46.1%,且耳蜗内毛细胞的突触复合体结构数量也减少了41.3%。而内毛细胞和螺旋神经节细胞没有明显丢失。结论听觉阈值功能测试对判断小鼠耳蜗内毛细胞突触的损害和丢失不敏感;而听觉阈上功能测试对评价小鼠耳蜗内毛细胞突触的损害和丢失相对敏感。
[Abstract]:Objective to investigate the pathological changes of the synapses of cochlear hair cells in mice with transient threshold shift after noise exposure. Methods the mice were divided into normal control group and experimental group. The experimental group mice were exposed to noise of 98 dB SPLL for 2 hours to establish a temporary threshold shift model. The control group and temporary threshold shift model mice were used to prepare the whole basement membrane and immunofluorescence staining. The confocal microscope was used to photograph and observe the morphology of the cells. The frequency position of cochlea was calculated by cochlea length. Finally, the synaptic structure was reconstructed by graphics processing software, and the presynaptic position of cochlear hair cells was observed in mice of control group and experimental group. The spatial distribution of post-structure and its pathological changes. Results the synaptic complex of the cochlear hair cells in the control group had obvious distribution characteristics. Each of the inner hair cells formed synaptic connections with the cochlear nerve fibers through 5 ~ 30 synapses, and the presynaptic structure near the cochlear axis was larger in volume. The corresponding postsynaptic structure is smaller in size. The volume of the presynaptic structure near the column cell side is smaller than that of the corresponding postsynaptic structure. The results of auditory tests on the second day after high intensity noise exposure showed that auditory brainstem response (auditory brain-stem responseABR) and distortion product otoacoustic emission (DPOAE) thresholds increased 30 ~ 40 dB ~ (2) weeks later, and showed that the thresholds returned to normal again, and the results showed that the auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE) thresholds increased 30 ~ 40 dB ~ (2) weeks after exposure. But the amplitude of wave I of ABR decreased by 46.1 and the number of synaptic complex of hair cells in cochlea decreased by 41.3%. There was no significant loss of inner hair cells and spiral ganglion cells. Conclusion the auditory threshold function test is not sensitive to the assessment of synapse damage and loss of mouse cochlear hair cells, while the auditory suprathreshold function test is relatively sensitive to the evaluation of the damage and loss of mouse cochlear hair cell synapses.
【作者单位】：复旦大学附属眼耳鼻喉医院耳鼻喉科;
【基金】：国家自然科学基金面上项目(81271084)~~
【分类号】：R764.43

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