摘要
目的探讨应用强化铁营养对抗稳态噪声致聋作用的可能性。方法４０只健康幼龄Ｗｉｓ－ｔａｒ大鼠按随机化原则分为两组，每组２０只：Ａ组饲标准饲料；Ｂ组饲强铁化饲料。将Ａ、Ｂ两组大鼠同时暴露于１１０ｄＢＳＰＬ２０～１００００Ｈｚ稳态白噪声，持续４０分钟。根据暴露前后听性脑干反应（ＡＢＲ）阈差值判定听力阈移，扫描电镜及光镜下观察耳蜗显微结构和听毛细胞表面超微结构变化。结果暴露后２小时、３天和１１天的Ｂ组听力阈移值显著小于Ａ组；暴露后２１天，虽然两组听力阈移均数值的差异无显著意义，但Ａ组ＡＢＲ阈值均数仍显著大于该组大鼠噪声暴露前平均听阈。扫描电镜下观察，暴露后２小时的Ａ组大鼠外毛细胞静纤毛出现严重扭曲、倒伏、排列紊乱等病理变化；３天后，上述病变明显减轻；２１天后，部分听毛细胞静纤毛排列紊乱仍未能完全恢复。在Ｂ组大鼠，外毛细胞静纤毛暴露２小时后有轻度扭曲及排列紊乱，３天后这些病变基本恢复，２１天后外毛细胞静纤毛形态完全恢复正常。结论强化铁营养具有对抗稳态噪声听损伤作用。
Objective To study the effects of fortified iron nutrition on hearing loss induced by steady state white noise.Methods 40 Wistar rats were randomized into two equal groups(A and B, each 20 animals). The group A rats were fed with normal dietary iron and the group B rats were fed with fortified iron nutrition diet. They were simultaneously exposed to a steady state white noise (20￣10 000 Hz) at 110 dB SPL for 40 min in a sound proof room. Hearing loss was determined by comparing the thresholds of auditory brainstem response(ABR) observed in the same animal before and after the noise exposure. The cochlear morphologic changes were examined with optic microscopy and scanning electron microscopy.Results The ABR threshold shifts at 2 h, 3 d and 11 d after the noise exposure in the group B rats were significantly smaller than those in the group A rats. No permanent threshold shift was seen in any of the group B rats. Whereas in the group A rats, the mean value of ABR threshold at 21 d after exposure was significantly higher than that before exposure. The pathologic changes of the outer hair cell stereocilia at 2 h after exposure were much less severe in group B than that in group A. And at 21 d after noise exposure, the stereocilia appeared perfectly normal and well defined in group B, where as there were still remained some abnormalities of stereocilia in group A.Conclusions Adequate and well designed fortified iron nutrition diet has the effect of preventing noise induced hearing loss, and the action mechanism may be related with its enhancing effect on the activity of iron containing enzymes.
基金
全军医药卫生科研基金
关键词
铁
稳态噪声
听损伤
静纤毛
Iron Noise,steady state Hearing loss Stereocilia
