脉冲噪声引起听毛损伤的扫描电镜观察

A SEM STUDY ON THE ACOUSTIC TRAUMA OF STEREOCILIA INDUCED BY IMPULSE NOISE

本研究针对中等强度脉冲噪声的作用,以扫描电镜观察了强度为115～135dB、脉宽为100～200ms和重复率为40～80次/min的A型脉冲噪声对豚鼠耳蜗毛细胞听毛的影响.试验组共24只耳蜗,分别给以115dB、125dB、135dB的噪声刺激,8只耳蜗作为正常对照.声暴露时间每天8h,7天后活杀,并3min之内取下耳蜗,常规方法制作标本,以日立S-520扫描电镜观察听毛改变.结果表明声暴露引起听毛损伤可分为四种改变,即松散、融合、倒伏和缺失.损伤部位以第二圈和第三圈比较明显,内毛细胞和外毛细胞的听毛损伤以第三排外毛细胞最为明显.115dB组听毛改变已经出现,125dB组有的改变更为明显,135dB组各种听毛损伤都比较严重.本研究对于了解中等强度脉冲噪声对耳蜗的损伤特点和制定有关噪声卫生标准提供了形态学依据.

Morphological changes of stereocilia of hair cells in guinea pig's cochlea caused by type A impulse noise of 115～135 dB SPL,100～200ms and 40～80 times per minute were observed with SEM.24 cochleas were stimulated with impulse noise in three groups of 115,125 and 135 dB SPL,and 8 normal cochleas were observed as controls.Noise exposure time was 8 hours.Guinea pigs were sacrificed 7 days after noise exposure.The cochleas were dissected in 3 minutes after death,processed by routine SEM method and observed with Hitachi S-520 SEM.Stereocilia damage includes looseness,fusion,collapse and loss,which are more significant on the second and the third turns than the rest turns of the cochlea,especially on the third row of outer hair cells.Acoustic trauma of stereocilia could be observed in 115 dB group,became more significant in 125 dB group,and were serious in 135 dB group.This study is helpful for understanding the effect of impulsc noise and working out hygienic standard of the noise.