【作者】 王勤瑛；

【导师】 华清泉；

【作者基本信息】 武汉大学 ， 耳鼻咽喉科学， 2004， 硕士

【摘要】 目的：探讨正常大鼠畸变产物耳声发射(DPOAE)的基本特征，为动物的筛选及动物模型建立的评估提供参考资料。研究大鼠单侧耳蜗损毁前后不同部位、不同时期，耳蜗核、下丘及听皮层中GABA能阳性神经元的分布及数量。 方法：采用CELESTA-503型耳声发射分析仪对40只(80耳)健康大鼠行DPOAE“听力图”和输入／输出曲线及阈值测试。按Catherine法对实验动物行单侧耳蜗毁损，标本行石蜡包埋、切片，并应用免疫组化方法(SP法)行耳蜗核、下丘及听皮层中GABA能阳性神经元分布的检测。 结果：1) 各频率的DPOAE检出率均为100％；1kHz的DPOAE幅值为17.60±5.96dBSPL，反应阈值为36.67±3.83dBSPL；2kHz以上DPOAE幅值均大于25dBSPL，反应阈值低于1kHz；I／O曲线表明各频率DPOAE幅值随初始音的强度上升而增加，两者间存在极为显著的相关性；同频率、同强度，DPOAE幅值、反应阈值，两耳间差异均无显著性(P＞0.05)。单侧耳蜗毁损后大鼠手术侧DPOAE幅值未引出。2) GABA能阳性神经元广泛分布于听觉中枢，听皮层中数量最多，耳蜗核次之，下丘中最少。GABA能神经元的体积，以下丘中最大、着色较深，听皮层次之、着色也较深，耳蜗核中最小、着色很深。耳蜗核中GABA能阳性神经元的数目：术后1至2周手术同侧明显低于对侧，术后3周上升，但仍少于手术对侧，至术后1月，手术同侧略少于对侧，且差异无显著性(P＞0.05)。下丘中GABA阳性神经元的数目：术后1至3周手术对侧明显低于同侧，至术后1月，手术对侧GABA阳性神经元的数目增加，但仍少于手术侧，且有显著性差异(P＜0.05)。听皮层中GABA阳性神经元的数目：术后1至2周手术对侧明显低于手术侧，术后3周上升，但仍少于手术侧，至术后1月，手术对侧略少于手术侧，且差异无显著性(P＞0.05)。 结论：1) 大鼠的DPOAE检出率高，幅值大，各项指标反应稳定。单侧耳蜗毁损动物可作为本研究的动物模型。2) 单侧耳蜗损毁前后，GABA能阳性神经元的分布在耳蜗核、下丘及听皮层中呈一明显的动态变化过程，说明GABA能神经元参与了耳蜗毁损后听觉中枢的可塑性变化或功能重组的过程，提示GABA能神经元数目的增减可能为听觉中枢的重组所必需。更多还原

【Abstract】 Object: To explore the basic properties of distortion product otoacoustic emission (DPOAE) in normal rats and to observe the distribution of gama-aminobutyric acid (GABA) ergic neurons in rat auditory center in pre and post-operation.Methods: DP-gram, I/O function curves and threshold of forty rats were measured by CELESTA-503 Cochlear Emission Analyzer. The technique of direct anti-GABA imrnunocytochemistry (SP) was used in this study.Results: 1) The incidence of DPOAE in all frequencies were 100%.The amplitude of DPOAE in 1kHz was 17.60?.96dBSPL. The amplitudes of DPOAE above 2kHz were larger than 25dBSPL. I/O function curves demonstrated that there was a significant relation betweem the amplitudes of DPOAE and the levels of primary stimuli in the statistics, that is, the higher levels of primary stimuli was, the larger amplitudes of DPOAE was. There was not a significant difference between left ears and right ears in all indeies. We could not obtain the amplitudes of DPOAE in lesion side of unilateral cochlea ablation rats. 2) The GABAergic neurons existed extensively in auditory center:auditory cortex(AC), inferior colliculus(IC) and cochlear nuclei(CN). But the number ,shape and staining of GABAergic neurons were different in every nucleus. AC had the largest number of GABAergic neuron, CN was second, IC had less GABAergic cells.The volume of GABAergic cells in IC was larger than those in AC and CN, and stained heavy. The GABA cells in CN was more heavily staining than those in IC and AC.In CN, the number of GABAergic cells in lesion side was less than those in intact side after unilateral cochlea ablation one to two weeks, then the number of GABAergic cells increased after three weeks and almost reached normal number in a month of post-operation,the difference has no statistically significance(P>0.05). In IC,the number of GABAergic cells in intact side was less than those in lesion side after unilateral cochlea ablation one to three weeks, then the number of GABAergic cells increased but stiil less than that of normal number in a month of post-operation,which showed significant difference between intact and lesion sides(P<0.05). In AC, the number of GABAergic cells in intact side was less than those in lesion side after unilateral cochlea ablation one to two weeks,then the number of GABAergic cells increased after three weeks and almost reached normal number in a month of post-operation(P>0.05).Conclusion: 1) In rats, the incidence of DPOAE was high, the amplitudes ofDPOAE was larger and all indeies were stabilization.The rat of unilateral cochlea ablation could serve for father study.2) The changes of GABAergic neurons reflect the balance between excitatory and inhibitory of neurons, it suggest that changes in the extent of GABAergic inhibition have been shown to contribute to the reorganization of auditory central system after unilateral cochlea ablation in rats.更多还原