Woolley S M, Wissman A M, Rubel E W
Neurobiology and Behavior Program, Department of Otolaryngology-HNS and Virginia Merrill Bloedel Hearing Research Center, P.O. Box 357923, University of Washington, Seattle, WA 98195, USA.
Hear Res. 2001 Mar;153(1-2):181-95. doi: 10.1016/s0378-5955(00)00217-3.
Birds regenerate auditory hair cells when original hair cells are lost. Regenerated hair cells become innervated and restore hearing function. Functional recovery during hair cell regeneration is particularly interesting in animals that depend on hearing for vocal communication. Bengalese finches are songbirds that depend on auditory feedback for normal song learning and maintenance. We examined the structural and functional recovery of the Bengalese finch basilar papilla after aminoglycoside ototoxicity. Birds were treated with the ototoxic aminoglycoside, amikacin, daily for 1 week. Treatment resulted in hair cell loss across the basal half of the basilar papilla and corresponding high frequency hearing loss. Hair cell regeneration and recovery of auditory brainstem responses were compared in the same animals. Survival times following treatment were between 1 day and 12 weeks. Analysis of structural recovery at weekly intervals indicated that hair cells in the Bengalese finch papilla require a maximum of 1 week to regenerate and appear with immature morphology at the epithelial surface. An additional 6 days are required for adult-like morphology to develop. Repopulation of the damaged region was complete by 8 weeks. Recovery of auditory thresholds began 1 week after treatment and reached asymptote by 4 weeks. Slight residual threshold shifts at 2.0 kHz and above were observed up to 12 weeks after treatment. Direct comparison of structural and functional recovery indicates that auditory thresholds recover maximally before a full complement of hair cells has regenerated.
当原始听觉毛细胞丢失时，鸟类能够再生听觉毛细胞。再生的毛细胞会重新获得神经支配并恢复听力功能。在依赖听力进行声音交流的动物中，毛细胞再生过程中的功能恢复尤其令人感兴趣。 Bengalese雀是鸣禽，依赖听觉反馈进行正常的歌声学习和维持。我们研究了氨基糖苷类耳毒性后Bengalese雀基底乳头的结构和功能恢复情况。鸟类每天接受耳毒性氨基糖苷类药物阿米卡星治疗，持续1周。治疗导致基底乳头基部一半的毛细胞丢失，并伴有相应的高频听力损失。在同一动物中比较了毛细胞再生和听觉脑干反应的恢复情况。治疗后的存活时间在1天至12周之间。每周进行一次结构恢复分析表明，Bengalese雀乳头中的毛细胞最多需要1周时间再生，并在上皮表面以不成熟的形态出现。还需要额外6天时间发育成类似成年的形态。受损区域在8周时重新填充完成。治疗1周后听觉阈值开始恢复，4周时达到稳定状态。治疗后12周内，在2.0 kHz及以上频率观察到轻微的残余阈值变化。结构和功能恢复的直接比较表明，在毛细胞完全再生之前，听觉阈值已最大程度地恢复。
