耳蜗外毛细胞静纤毛束变异的判定标准研究

目的建立耳蜗外毛细胞(OHCs)静纤毛束变异的形态学统一判定标准。方法光镜和扫描电镜观察豚鼠耳蜗OHCs静纤毛束变异形态学特征及听觉诱发电位(ABR)、听神经动作电位(CAPs)和耳声发射畸变产物(DPOAE)参数改变。结果在100只实验豚鼠中,有28%的动物OHCs静纤毛束变异;OHC1变异最多见转位90°,常可见连续数个毛细胞90°转向蜗底,部分毛细胞静纤毛束“W”型转位达180°。结论我们拟定耳蜗外毛细胞静纤毛束变异的标准为:①超过10%的耳蜗第一排外毛细胞静纤毛束的“W”型变形及转向,毛细胞由45°转位至90°改变,多向基底方向,且呈双侧性。②毛细胞静纤毛束变异程度分为Ⅰ型:50%的OHC变异为重度变异;Ⅱ型:30%的OHCs变异为中度变异;Ⅲ型:10%以上的OHCs变异为轻度变异;③耳蜗毛细胞静纤毛束变异动物的双侧耳听功能(ABR、CAP、DPOAE)改变。

Assessment criteria for rotated stereociliary bundles in the guinea pig cochlea

Objective To establish the assessment criteria for rotated stereociliary bundles in the guinea pig cochlea. Methods Auditory brainstem responses(ABR) and otoacoustic emission of distortion products(DPOAE) were assayed in 28 guinea pigs of the rotated stereociliary bundles. Scanning electron microscopy and light microscopy were used to observe the angle of rotated stereociliary bundles from the normal orientation and to count the percentage of rotated hair cells, respectively. Results The perentage of rotated hair cells was estimated to be 28% in affected animals.The anomaly was clearly most severe among the first-row OHCs. On affected OHC_1 the hair hundles appeared to be rotated by 90° from the normal orientation. Conclusion The assessment criteria we have established for the rotated stereociliary bundles was that when it was over 10% of OHC_1 the hair bundles appear to be rotated by 90°from the normal orientation; according to the degree of stereociliary bundles variations, they could be classified as follows: severe: variant OHC ≥50%; ② moderate ≥20%; ③ mild: individual OHCs variations. ABR threshold of these animals increased slightly while amplitude of DPOAE increased significantly.