Wang Lin-e, Cao Ke-li, Yin Shan-kai, Wang Zhen, Chen Zheng-nong
Department of Otolaryngology, Shanghai Sixth People's Hospital of Shanghai Jiao Tong University, Shanghai 200233, China.
Chin Med J (Engl). 2006 Jun 20;119(12):974-9.
Ouabain, a cardiac glycoside that specifically binds to Na/K-ATPase and inhibits its activity, was applied to gerbils to develop a method for studying auditory neuropathy.
Ouabain was applied to the round window of the cochlea in each gerbil by using a piece of gelfoam with 3 microl or 24 microl (1 mmol/L) ouabain solution. The changes of the threshold of auditory brainstem response, cochlear function round window electrocochleography, as well as the morphological changes of the spiral ganglion cells of the cochlea were observed after application of ouabain for 24 hours or 96 hours.
In ouabain treated gerbils, auditory brainstem response and compound action potential thresholds showed either elevation or no response at all. However, the thresholds of cochlear microphonic and distortion product otoacoustic emissions were not affected. Degeneration and necrosis of some spiral ganglion cells in ears with applications of ouabain (24 hours, 3 microl, 1 mmol/L; 96 hours, 24 microl, 1 mmol/L ouabain). The number of spiral ganglion cells was decreased (24 hours, 3 microl, 1 mmol/L ouabain) or near to a total loss (96 hours, 24 microl, 1 mmol/L ouabain).
These results indicate a high degree of independence between the spiral ganglion cells and the outer hair cell systems in the cochlear transduction mechanism. The method used in this study would provide a valuable tool for studying auditory neuropathy.
哇巴因是一种特异性结合钠钾ATP酶并抑制其活性的强心苷，被应用于沙鼠以开发一种研究听觉神经病变的方法。
通过使用一块含有3微升或24微升（1毫摩尔/升）哇巴因溶液的明胶海绵，将哇巴因应用于每只沙鼠耳蜗的圆窗。在应用哇巴因24小时或96小时后，观察听觉脑干反应阈值、耳蜗功能圆窗电耳蜗图的变化以及耳蜗螺旋神经节细胞的形态变化。
在接受哇巴因治疗的沙鼠中，听觉脑干反应和复合动作电位阈值要么升高，要么完全无反应。然而，耳蜗微音电位和畸变产物耳声发射的阈值未受影响。在应用哇巴因（24小时，3微升，1毫摩尔/升；96小时，24微升，1毫摩尔/升哇巴因）的耳朵中，一些螺旋神经节细胞发生变性和坏死。螺旋神经节细胞数量减少（24小时，3微升，1毫摩尔/升哇巴因）或接近完全丧失（96小时，24微升，1毫摩尔/升哇巴因）。
这些结果表明在耳蜗转导机制中，螺旋神经节细胞和外毛细胞系统之间具有高度的独立性。本研究中使用的方法将为研究听觉神经病变提供一个有价值的工具。
