OTOTOXIC MECHANISMS OF GENTAMICIN ON SENSORY HAIR CELLS

庆大霉素对感觉毛细胞的耳毒性机制

• 批准号: 3424682
• 负责人: HONG Y YAN
• 金额: $ 3.37万
• 依托单位: UNIV OF MARYLAND, COLLEGE PARK
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-07-01 至 1993-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3424682
• 关键词: antiserum; autoradiography; drug receptors; ear hair cell; fish; gentamicins; immunocytochemistry; light microscopy; lithium; ototoxin; phosphatidylinositols; transmission electron microscopy; tritium

This proposal is intended at addressing a major question with regard to selective ototoxic damage to sensory hair cells of the fish ear caused by one aminoglycoside antibiotic, gentamicin sulfate. Recently we demonstrated that only striolar hair cells in the utricular and lagenar otolithic endorgans of fish ear are susceptible to gentamicin sulfate assault. The same type of selective damage to the cochlear outer hair cells and type I hair cells of vestibular endorgans have also been reported in mammalian species. These identical damage patterns between fish and mammals justify the fish ear as a valuable model system for the proposed study. Three hypotheses are proposed and will be used to elucidate mechanisms leading to selective damage to sensory hair cells caused by gentamicin. 1) "Receptor Presence " hypothesis predicts differential distribution of gentamicin receptors between the two types of hair cells. It will be tested by localizing the presence of gentamicin receptors, i.e., phosphoinositide (PIP2). Immuno-gold transmission electron immunocytochemical procedures with antisera raised against the receptor will be used to detect the distribution of receptors between striolar and extrastriolar hair cells. 2) "Route Pathways" hypothesis predicts spatial and temporal difference in uptake routes of gentamicin between the two cell types. The hypothesis will be tested by using both autoradiography and immunocytochemistry methods. Tritiated gentamicin will be used to visualize the intracellular presence of gentamicin under light microscopy. Antisera raised against gentamicin will be used in conjunction with immuno-gold to examine intracellular targets of gentamicin under transmission electron microscope. 3) "Lithium blockage" hypothesis predicts that if gentamicin receptors could be blocked then no ototoxic damage should be observed. The hypothesis will be tested by using lithium, a known inhibitor of PIP2, through systemic injection and direct application into otolithic endorgans in conjunction with injections of gentamicin. "Lithium blockage" hypothesis could be proved if no ototoxic damage is detected at striolar hair cells.

该提案旨在解决有关的一个重大问题 鱼耳感觉毛细胞的选择性耳毒性损伤 一种氨基糖苷类抗生素，硫酸庆大霉素。 最近我们 证明只有椭圆形毛细胞和内毛细胞 鱼耳的耳石内器官对硫酸庆大霉素敏感 突击。 同类型的耳蜗外毛选择性损伤 前庭内器官的细胞和 I 型毛细胞也已被 在哺乳动物物种中已有报道。 这些相同的损坏模式之间 鱼类和哺乳动物证明鱼耳是一个有价值的模型系统 提议的研究。 提出了三个假设，将用于阐明机制 导致庆大霉素对感觉毛细胞造成选择性损伤。 1)“受体存在”假设预测了差异分布 两种毛细胞之间的庆大霉素受体。 这将是 通过定位庆大霉素受体的存在进行测试，即 磷酸肌醇（PIP2）。 免疫金透射电子 使用针对受体的抗血清进行免疫细胞化学程序 将用于检测纹状体和纹状体之间受体的分布 房外毛细胞。 2）“路线路径”假说预测空间 以及两者之间庆大霉素摄取途径的时间差异 细胞类型。 该假设将通过放射自显影技术进行检验 和免疫细胞化学方法。 氚化庆大霉素将用于 在光下可视化细胞内庆大霉素的存在 显微镜。 针对庆大霉素的抗血清将用于 与免疫金结合检查细胞内靶标 透射电子显微镜下的庆大霉素。 3）“锂堵塞” 假说预测，如果庆大霉素受体可以被阻断，那么就不会 应观察耳毒性损伤。 该假设将通过以下方式进行检验 通过全身注射使用锂（一种已知的 PIP2 抑制剂） 直接应用于耳石内器官 注射庆大霉素。 “锂堵塞”假说得以证实 如果纹状毛细胞没有检测到耳毒性损伤。