脉冲噪声暴露后耳蜗螺旋器超微结构的变化

Ultrastructural Changes in the Spiral Organ of Cochlea after Exposure to Impulse Noise

本文报告脉冲噪声暴露后不同时相耳蜗螺旋器超微结构的变化。受试豚鼠暴露脉宽为0.1 ms,峰值166dB SPL脉冲噪声10发。其中13只豚鼠在脉冲噪声暴露后30min至30d内不同时相分别测试阈移,系统观察阈移恢复变化。其余14只动物分别在相同时相断头处死,制备透射电镜标本和观察。结果显示,脉冲噪声暴露后阈移恢复类型呈非单调型,暴露后30min～8h内,毛细胞内变性逐渐加重,并在暴露后8h达最高峰,细胞内水肿和肿胀形成毛细胞变形,静纤毛融合,大空泡在细胞内形成和表面囊肿胀在此时刻最严重。8h后细胞变性程度变轻。本实验结果显示,脉冲噪声暴露后耳蜗螺旋器变化的时间顺序与阈移恢复类型有关。

Ultrastructural changes in the spiral organ of cochlea at various intervals after exposure to impulse noise were investigated. Guinea pigs were exposed to 10 impulses noise of 166 dB SPL peak level which had duration of 0.1 ms. Thirteen of the exposed animals were used to systematically measure threshold shift at regular intervals from 30 min to 30d post-exposure. The other fourteen animals who had been exposed to the same impulse noise were killed for transmission electron microscopy (TEM) examination at the same intervals, respectively. The recovery pattern of threshold shift showed a nonmonotonic type. There was a progressive deterioration of changes in the hair cells between 30 min and 8h after exposure. Intracellular degeneration reached a peak at 8h and marked edema and swelling leading to deformation of the outer hair cells (OHCs), fused stereocilia, large vesicles in cytoplasm and swollen submembraneous cisterns were found. After that time the extent of degeneration in the hair cells reduced. The time sequence of changes in the spiral organ of cochlea in the present study was associated with the recovery pattern of threshold shift.