Vestibular Hair Cell Regeneration

描述(由申请人提供)：本项目的目的是研究在外科手术内注射庆大霉素(GM)后，成年龙猫内耳恢复水平前庭毛细胞的形态、生理和分子机制。庆大霉素是前庭研究的著名模型。实验方案的设计假设是，GM的作用是剂量和区域依赖的，有效耳毒性剂量相差三倍，I型毛细胞比II型毛细胞更敏感。I型毛细胞之间也有差异，这与它们在不同的脊带中的位置有关。当每种毛细胞的治疗剂量都在特定的致离子耳毒性范围内时，不同毛细胞的自发再生就会发生。具体目的包括以下研究：1)研究四种药物动力学选择剂量的GM对感觉细胞和神经元的损伤和再生的时间进程；2)平行测量前庭眼球反射(VOR)功能和单个前庭神经纤维的生理反应的变化，并将其与解剖学变化进行比较；3)研究BDNF、FGF-2及其组合在VOR和毛细胞中潜在的神经营养因子保护作用。解剖和生理变化将在基于解剖学和生理学原理和初步研究结果的病理-生理学克里斯塔模型的背景下进行评估。应用的技术包括组织学、免疫组织化学、荧光和共聚焦显微镜、用一种新的非侵入性动物前庭眼底成像技术进行计算机测量以测试VOR功能和电生理单纤维记录法。经过十多年的研究，哺乳动物前庭毛细胞的解剖和功能再生能力的控制仍然没有解决。然而，我们的初步结果提供了毛细胞自发再生的能力和研究策略的证据，这些研究策略将使我们更接近毛细胞医疗时代，以缓解目前无法治愈的疾病的祸害，这些疾病会导致失衡和耳聋。加深对这些过程的了解将催生关于前庭器官正常功能的新概念，并导致预防与GM等药物相关的并发症的方法/治疗，这些药物被广泛用于挽救生命的细菌感染，如梅尼埃耳科的其他治疗目的。

DESCRIPTION (provided by applicant): The objective of this project is to investigate the morphological, physiological and molecular mechanisms of recovery of the horizontal crista vestibularis hair cells following surgical intraotic administration of gentamicin (GM) in the inner ear of adult chinchillas, a well known model for vestibular research. The experimental protocol is designed with the hypothesis that the effect of GM is dose and zone dependent with a threefold difference in the effective ototoxic dose, with type I hair cells being more sensitive than type II hair cells. Among type I hair cells there are also differences related to their location in different crista zones. Spontaneous regeneration of different hair cells takes place when each type is treated with doses that fall within the specific iaotrogenic ototoxic range. The specific aims include the following studies: 1) Investigation of the temporal course of damage and regeneration of the sensory cells and neurons following four pharmaco-kinetically selected doses of GM; 2) Parallel measurements of the changes in the Vestibulo Ocular Reflex (VOR) function and of single vestibular nerve fibers physiological responses to be compared with the anatomical changes; 3) Investigation of the potential protective neurotrophins effect of BDNF, FGF-2, and a combination of both in the VOR and hair cells. The anatomical and physiological changes will be evaluated in the context of a patho-physiological crista model based on anatomical and physiological principles and on the results of the preliminary studies findings. The applied techniques include histology, immunohistochemistry, fluorescence and confocal microscopy, computerized measurements with a new non-invasive animal technique of vestibule oculography for VOR function testing and electrophysiological single fiber recording methods. After more than a decade of research, the control of the anatomical and functional regeneration capacity of vestibular hair cells in mammals remains unresolved. However, our preliminary results have provided evidence of the capacity of spontaneous hair cell regeneration and the research strategies that will place us closer to the era of hair cell medical treatments for the relief of the scourge of presently untreatable diseases that cause disequilibrium and deafness. Advancing the understanding of these processes will precipitate new concepts regarding the normal function of the vestibular organs and lead to methods/treatment preventing complications associated with drugs like GM that are widely used in life saving bacterial infections on other therapeutic otological objectives as in Meniere's.