Preventing Hearing Damage Using Topical Dexamethasone During Reversible Cochlear Ischemia: An Animal Model
Preventing Hearing Damage Using Topical Dexamethasone During Reversible Cochlear Ischemia: An Animal Model
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DOI：
10.1097/mao.0b013e3181b12296
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发表时间：
2009-09-01
影响因子：
2.1
通讯作者：
Niemczyk, Kazimierz
中科院分区：
文献类型：
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作者：
Morawski, Krzysztof;Telischi, Fred F.;Niemczyk, Kazimierz
假设：局部应用地塞米松的圆窗（RW）niche防止局部可逆性ischemia.Background：耳蜗缺血引起的内耳动脉（IAA）的压缩/拉伸被认为是导致术后感觉性听力损失后，试图保留听力的听神经瘤肿瘤切除术。地塞米松给药的RW龛旅行通过膜的耳蜗fluids.Materials和方法：10个年轻的白化病兔用于这项研究。通过挤压IAA诱导缺血发作。激光多普勒耳蜗血流测量使用探头定位在RW龛。在4、8和12 kHz下测量经鼓膜耳蜗电图。在5只试验耳中，在IAA按压之前在RW处局部施用地塞米松约50分钟，而在5只对照耳中，以相同的方式施用盐水。每只耳朵进行了一个10分钟的IAA压缩60分钟postischemic期间transstympanic electrococle描记monitoring.Results：在这两个控制和地塞米松治疗的耳朵，缺血发作测量激光多普勒耳蜗血流是可比的。IAA减压后50分钟，在地塞米松预处理的耳朵，耳蜗微音器和复合动作电位振幅在所有测试频率减少10至15%，比对照耳。复合动作电位潜伏期在地塞米松预处理的耳朵导致较短的潜伏期延迟比对照ears.Conclusion：RW似乎是一种有效的途径地塞米松给药到内耳。地塞米松对局部缺血后耳蜗功能有保护作用。经鼓膜耳蜗电图被认为是一个足够的和有效的工具，在监测听力。
Hypothesis: Local application of dexamethasone to the round window (RW) niche prevents cochlear damage caused by local reversible ischemia.Background: Cochlear ischemia induced by internal auditory artery (IAA) compression/stretching is thought to cause postoperative sensory hearing loss after attempted hearing preservation removal of acoustic neuroma tumors. Dexamethasone administered to the RW niche traveling through the membrane to the cochlear fluids may prevent ischemic damage.Materials and Methods: Ten young albino rabbits were used for this study. Ischemic episodes were induced by compressing the IAA. Laser Doppler cochlear blood flow was measured using a probe positioned at the RW niche. Transtympanic electrocochleography was measured at 4, 8, and 12 kHz. In 5 test ears, dexamethasone was administered topically at the RW for approximately 50 minutes before the IAA compressions, whereas in 5 control ears, saline was applied in the same way. Each ear underwent one 10-minute IAA compression with a 60-minute postischemic period of transtympanic electrocochleography monitoring.Results: In both control- and dexamethasone-treated ears, ischemic episodes measured by Laser Doppler cochlear blood flow were comparable. Fifty minutes after IAA decompression, in dexamethasone-pretreated ears, cochlear microphonic and compound action potential amplitudes at all test frequencies were 10 to 15% less reduced than those in control ears. Compound action potential latencies in dexamethasone-pretreated ears resulted in shorter latency delay than in control ears.Conclusion: The RW seems to be an efficacious route for the administration of dexamethasone into the inner ear. Dexamethasone showed a protective effect on cochlear function after local ischemia. Transtympanic electrocochleography was found to be a sufficient and effective tool in monitoring hearing.