Suryadevara Amar C, Wanamaker Hayes H, Pack Adam
Department of Otolaryngology and Communication Sciences, SUNY Upstate Medical University, Syracuse, New York, USA.
Laryngoscope. 2009 Jun;119(6):1166-70. doi: 10.1002/lary.20145.
OBJECTIVES/HYPOTHESIS: Recent studies in animal models have shown via physiologic and histologic measures that the administration of exogenous antioxidants is protective against gentamicin-induced oto-vestibulo toxicity. In addition, studies have also shown that sound conditioning increases cochlear antioxidants. The objective of this study is to determine whether sound conditioning provides protection against gentamicin in the cochlear and/or vestibular system.
: Prospective animal study.
Three-month-old gerbils were divided into three groups (A, B, and C). The gerbils in group A were sound conditioned only (n = 2). In group B, the animals received gentamicin on the round window (n = 2). The gerbils in group C were sound conditioned first and later received gentamicin to the round window (n = 2). The animals were ultimately sacrificed and their right cochlea and posterior crista ampullaris were removed, processed, and sectioned. The specimens were analyzed for inner hair cell (IHC) and outer hair cell (OHC) loss and vestibular supporting and sensory hair cell nuclei per micrometer of vestibular epithelium.
The sound-conditioned group (A) had no loss of cochlear hair cells. The gerbils treated with gentamicin only (B) had a 34% decrease of OHCs and 49% decrease of IHCs. The sound-conditioned plus gentamicin-treated group (C) had a 5.5% decrease in OHCs and 12% decrease in IHCs. There were no significant differences with regards to supporting cell nuclei within the posterior crista across all groups. When compared to group A, the gerbils in groups B and C did have a 23 to 42% decrease in the number of sensory cell nuclei per micrometer of vestibular epithelium.
Sound conditioning does appear to attenuate the effects of gentamicin in the cochlea, although not significantly altering its vestibulotoxicity. An upregulation of cochlear-specific antioxidants is believed to be an important factor. As we had a small sample size, we can only note trends in the data, but future studies with more animals and measurements of antioxidant levels after sound conditioning would be useful to quantify this effect and determine if it can be exploited clinically. Laryngoscope, 2009.
目的/假设：近期在动物模型中的研究通过生理学和组织学测量表明，给予外源性抗氧化剂可预防庆大霉素引起的耳-前庭毒性。此外，研究还表明声音预处理可增加耳蜗抗氧化剂。本研究的目的是确定声音预处理是否能在耳蜗和/或前庭系统中预防庆大霉素的损害。
前瞻性动物研究。
将3个月大的沙鼠分为三组（A组、B组和C组）。A组沙鼠仅进行声音预处理（n = 2）。B组动物在圆窗给予庆大霉素（n = 2）。C组沙鼠先进行声音预处理，随后在圆窗给予庆大霉素（n = 2）。最终处死动物，取出其右侧耳蜗和后半规管壶腹嵴，进行处理和切片。分析标本中每微米前庭上皮内的内毛细胞（IHC）和外毛细胞（OHC）损失情况以及前庭支持细胞和感觉毛细胞核数量。
声音预处理组（A组）耳蜗毛细胞无损失。仅接受庆大霉素治疗的沙鼠（B组）外毛细胞减少34%，内毛细胞减少49%。声音预处理加庆大霉素治疗组（C组）外毛细胞减少5.5%，内毛细胞减少12%。所有组后半规管内支持细胞核数量无显著差异。与A组相比，B组和C组沙鼠每微米前庭上皮内感觉细胞核数量减少23%至42%。
声音预处理似乎确实能减轻庆大霉素对耳蜗的影响，尽管对其前庭毒性没有显著改变。耳蜗特异性抗氧化剂的上调被认为是一个重要因素。由于我们的样本量较小，只能注意到数据中的趋势，但未来使用更多动物并在声音预处理后测量抗氧化剂水平的研究将有助于量化这种效应，并确定其是否可在临床上加以利用。《喉镜》，2009年
