Okuda Takeshi, Sugahara Kazuma, Shimogori Hiroaki, Yamashita Hiroshi
Department of Otolaryngology, Yamaguchi University School of Medicine, Yamaguchi, Japan.
Laryngoscope. 2004 Apr;114(4):694-7. doi: 10.1097/00005537-200404000-00018.
OBJECTIVES/HYPOTHESIS: Transtympanic administration of gentamicin is reported to be a useful treatment for vertigo in such conditions as Meniere's disease, and determining appropriate clinical dosage of gentamicin is difficult. The authors examined the relation between gentamicin dosages and inner ear function in guinea pigs.
This study is a basic science project designed to examine cochlear and vestibular function in animal models.
Various concentrations of gentamicin solution were infused into the right inner ear of guinea pigs by osmotic pumps. Caloric nystagmus as a marker of vestibular function and the change in auditory brainstem response (ABR) threshold as a marker of cochlear function were observed.
After 14 days of treatment, high gentamicin concentrations of 40 mg/mL caused canal paralysis and a rapid shift in ABR threshold. Animals exposed to low gentamicin concentrations of 4 mg/mL showed no obvious change in either vestibular or cochlear function. Animals exposed to moderate gentamicin concentrations of 12 mg/mL showed a moderate shift in ABR threshold and caloric malfunction. Histopathological examination revealed that after 14 days of treatment with 40 mg/mL gentamicin, severe cytoplasmic damage occurred in both vestibular and cochlear end organs. In animals treated with 12 mg/mL gentamicin, hair cells remained in the cochlear third turn and ampulla of the lateral semicircular canal.
The authors established an animal model that showed the moderate damage of inner ear with moderate-dose gentamicin. The study results indicated that the appropriate administration of gentamicin could establish a stable effect on the inner ear. It may be important to select the protocol that delivers a stable dosage of gentamicin to treat patients with Meniere's disease safely and effectively.
目的/假设：据报道，鼓室内注射庆大霉素是治疗梅尼埃病等疾病所致眩晕的一种有效方法，而确定庆大霉素的合适临床剂量具有一定难度。作者研究了豚鼠体内庆大霉素剂量与内耳功能之间的关系。
本研究是一项基础科学项目，旨在检测动物模型中的耳蜗和前庭功能。
通过渗透泵将不同浓度的庆大霉素溶液注入豚鼠右内耳。观察作为前庭功能标志物的冷热眼震以及作为耳蜗功能标志物的听性脑干反应（ABR）阈值的变化。
治疗14天后，40mg/mL的高浓度庆大霉素导致半规管麻痹以及ABR阈值迅速变化。暴露于4mg/mL低浓度庆大霉素的动物，其前庭或耳蜗功能均未出现明显变化。暴露于12mg/mL中等浓度庆大霉素的动物，ABR阈值出现中等程度变化且冷热试验功能异常。组织病理学检查显示，用40mg/mL庆大霉素治疗14天后，前庭和耳蜗终器均出现严重的细胞质损伤。在用12mg/mL庆大霉素治疗的动物中，耳蜗第三圈和外侧半规管壶腹处仍有毛细胞。
作者建立了一个动物模型，该模型显示中等剂量庆大霉素会对内耳造成中度损伤。研究结果表明，适当使用庆大霉素可对内耳产生稳定的作用。选择能提供稳定剂量庆大霉素的方案对于安全有效地治疗梅尼埃病患者可能很重要。
