Department of Otolaryngology, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, China.
Am J Otolaryngol. 2013 May-Jun;34(3):209-15. doi: 10.1016/j.amjoto.2012.11.015. Epub 2013 Jan 16.
Magnesium is proved to attenuate acoustic trauma, and reactive oxygen species (ROS) formation is a critical role that involves hearing loss induced by impulse noise. We aimed to investigate the relationship between the cochlea magnesium content, ROS formation and hearing loss induced by impulse noise.
Ninety pigmented guinea pigs were exposed to impulse noise. Auditory thresholds were assessed by sound-evoked auditory brainstem response (ABR) 24h before and 72h after exposure to impulse noise. 4-Hydroxynonenal(HNE) used as a marker of ROS was determined immunohistochemically. The cochlea magnesium content was examined with the method of energy dispersive x-ray analysis, and the cochlea was also detected with scanning electron microscope. The relationship between the cochlea magnesium content, ROS formation and hearing loss was analyzed.
There was loss of outer hair cell cilia accompanying with significant auditory threshold shift after impulse noise exposure. ROS was positive in the organ of Corti of all animals. The cochlea magnesium content was negatively correlated with ROS formation and hearing loss.
Inhibiting ROS formation is one of the mechanisms for magnesium to reduce acoustic trauma, and difference in cochlea magnesium contents is one of the factors that induce varying degrees of cochlear damage among each individual after acoustic trauma.
镁已被证实可减轻声损伤，而活性氧（ROS）的形成在脉冲噪声引起的听力损失中起着关键作用。本研究旨在探讨耳蜗内镁含量、ROS 形成与脉冲噪声性听力损失之间的关系。
90 只有色豚鼠暴露于脉冲噪声中。在暴露于脉冲噪声前 24 小时和后 72 小时，通过声诱发听性脑干反应（ABR）评估听觉阈值。用免疫组织化学法测定 4-羟壬烯醛（HNE）作为 ROS 的标志物。用能谱 X 射线分析法检测耳蜗镁含量，并用扫描电子显微镜检测耳蜗。分析耳蜗镁含量、ROS 形成与听力损失之间的关系。
脉冲噪声暴露后，外毛细胞纤毛丢失，听阈明显改变。所有动物的 Corti 器中均有 ROS 阳性。耳蜗镁含量与 ROS 形成和听力损失呈负相关。
抑制 ROS 形成是镁减轻声损伤的机制之一，耳蜗内镁含量的差异是导致每个个体在声损伤后发生不同程度耳蜗损伤的因素之一。
