Xiong Min, He Qinglian, Lai Huangwen, Wang Jian
Department of Otolaryngology, General Hospital of PLA Guangzhou Command, China.
Acta Otolaryngol. 2011 Sep;131(9):914-20. doi: 10.3109/00016489.2011.577448. Epub 2011 May 4.
The results suggest that melanin inhibits formation of reactive oxygen species (ROS) and prevents apoptosis in spiral ganglion cells (SGCs) of pigmented guinea pigs following impulse noise.
The stria vascularis of pigmented guinea pig cochlea contains melanocytes that produce melanin, which has a protective effect on noise-induced hair cell damage through its antioxidant property. ROS are involved in cochlear damage induced by impulse noise trauma. The purpose of the present study was to investigate the oxidative stress in SGCs of pigmented and albino guinea pigs after exposure to impulse noise.
Pigmented and albino guinea pigs were exposed to impulse noise. Auditory thresholds were assessed by sound-evoked auditory brainstem response (ABR) before impulse noise exposure and 72 h after impulse noise exposure. 4-Hydroxynonenal (HNE) was used as a histochemical marker of ROS formation, and active-caspase-3 (cas-3) served as a marker for apoptosis. 4-HNE and cas-3 were determined immunohistochemically. Hair cell damage was analyzed by scanning electron microscopy.
The rates of 4-HNE-positive and cas-3-positive SGCs in pigmented guinea pigs were much less than those for albino guinea pigs. Correspondingly, there was less hair cell damage and reduced ABR threshold shifts in pigmented guinea pigs.
结果表明，黑色素可抑制活性氧（ROS）的形成，并防止有色豚鼠在受到脉冲噪声后螺旋神经节细胞（SGC）发生凋亡。
有色豚鼠耳蜗的血管纹含有产生黑色素的黑素细胞，黑色素通过其抗氧化特性对噪声诱导的毛细胞损伤具有保护作用。ROS参与脉冲噪声创伤引起的耳蜗损伤。本研究的目的是调查暴露于脉冲噪声后有色和白化豚鼠SGC中的氧化应激。
将有色和白化豚鼠暴露于脉冲噪声。在脉冲噪声暴露前和暴露后72小时，通过声诱发听觉脑干反应（ABR）评估听觉阈值。4-羟基壬烯醛（HNE）用作ROS形成的组织化学标记物，活性半胱天冬酶-3（cas-3）用作凋亡标记物。通过免疫组织化学法测定HNE和cas-3。通过扫描电子显微镜分析毛细胞损伤。
有色豚鼠中4-HNE阳性和cas-3阳性SGC的比例远低于白化豚鼠。相应地，有色豚鼠的毛细胞损伤较少，ABR阈值变化也较小。
