Versnel Huib, Agterberg Martijn J H, de Groot John C M J, Smoorenburg Guido F, Klis Sjaak F L
Department of Otorhinolaryngology, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, 3508 GA Utrecht, The Netherlands.
Hear Res. 2007 Sep;231(1-2):1-12. doi: 10.1016/j.heares.2007.03.003. Epub 2007 Mar 31.
In animal models of deafness, administration of an aminoglycoside in combination with a loop diuretic is often applied to produce a rapid loss of cochlear hair cells. However, the extent to which surviving hair cells remain functional after such a deafening procedure varies. In a longitudinal electrocochleographical study, we investigated the variability of cochlear function between and within guinea pigs after combined administration of kanamycin and furosemide. Concurrently, histological data were obtained at 1, 2, 4 and 8 weeks after deafening treatment. The main measures in our study were compound action potential (CAP) thresholds, percentage of surviving hair cells and packing density of spiral ganglion cells (SGCs). One day after deafening treatment, we found threshold shifts widely varying among animals from 0 to 100dB. The variability decreased after 2 days, and in 18 out of 20 animals threshold shifts greater than 55dB were found 4-7 days after deafening. Remarkably, in the majority of animals, thresholds decreased by up to 25dB after 7 days indicating functional recovery. As expected, final thresholds were negatively correlated to the percentage of surviving hair cells. Notably, the percentage of surviving hair cells might be predicted on the basis of thresholds observed one day after deafening. SGC packing density, which rapidly decreased with the period after deafening treatment and correlated to the percentage of surviving inner hair cells, was not a determining factor for the CAP thresholds.
在耳聋动物模型中，常联合使用氨基糖苷类药物和袢利尿剂以快速导致耳蜗毛细胞丧失。然而，在这种致聋过程后存活的毛细胞仍保持功能的程度存在差异。在一项纵向耳蜗电图研究中，我们调查了豚鼠在联合给予卡那霉素和速尿后耳蜗功能在不同个体间以及个体内部的变异性。同时，在致聋治疗后1、2、4和8周获取组织学数据。我们研究中的主要测量指标是复合动作电位（CAP）阈值、存活毛细胞百分比和螺旋神经节细胞（SGCs）的堆积密度。致聋治疗后一天，我们发现动物之间的阈值变化范围很广，从0到100dB。2天后变异性降低，并且在20只动物中有18只在致聋后4 - 7天发现阈值变化大于55dB。值得注意的是，在大多数动物中，7天后阈值降低多达25dB，表明功能恢复。正如预期的那样，最终阈值与存活毛细胞百分比呈负相关。值得注意的是，存活毛细胞百分比可以根据致聋后一天观察到的阈值来预测。SGC堆积密度随着致聋治疗后的时间迅速降低，并且与存活内毛细胞百分比相关，但它不是CAP阈值的决定因素。
