Quint E, Furness D N, Hackney C M
Department of Communication and Neuroscience, Keele University, Staffs, UK.
Hear Res. 1998 Apr;118(1-2):157-67. doi: 10.1016/s0378-5955(98)00026-4.
Recent reports suggest that immature hair bundles are observed following aminoglycoside-induced hair-cell loss in the mammalian utricle in vitro as well as in vivo. It is therefore important to document the initial morphological changes associated with both culturing and aminoglycoside application so that degeneration can be clearly distinguished from regeneration. In this study, utricles from adult guinea pigs were maintained in culture for either 3 or 8 days, half being exposed to neomycin for days 2 and 3. They were then processed for microscopical examination and compared with control utricles from animals of the same age. The numbers of hair-cell and supporting-cell nuclei were counted and hair-cell morphology assessed. Bundles were classified as having either stepped (SHB) or unstepped (UHB) stereocilia, and their density determined. The numbers of hair-cell, but not supporting-cell, nuclei declined significantly compared with controls in both untreated and treated explants, the greatest reduction occurring 5 days after neomycin administration. The density of SHBs also declined but there was no significant change in UHB density, resulting in a residual population of hair bundles of more immature appearance in both untreated and treated utricles in vitro than in vivo. Although degenerative events such as hair-cell ejection from, or retraction into, the sensory epithelium were observed, no evidence of regeneration was found.
最近的报告表明，在体外以及体内的哺乳动物椭圆囊中，氨基糖苷类药物诱导毛细胞损失后可观察到未成熟的毛束。因此，记录与培养和应用氨基糖苷类药物相关的初始形态变化非常重要，以便能够清楚地区分退化和再生。在本研究中，将成年豚鼠的椭圆囊在培养中维持3天或8天，其中一半在第2天和第3天暴露于新霉素。然后对其进行显微镜检查，并与同龄动物的对照椭圆囊进行比较。对毛细胞和支持细胞核的数量进行计数，并评估毛细胞形态。将毛束分类为具有阶梯状（SHB）或非阶梯状（UHB）静纤毛，并测定其密度。与对照相比，未处理和处理过的外植体中毛细胞核的数量均显著下降，但支持细胞核的数量没有显著变化，最大减少发生在给予新霉素后5天。SHB的密度也下降，但UHB密度没有显著变化，导致体外未处理和处理过的椭圆囊中毛束的残留群体比体内的外观更不成熟。虽然观察到了诸如毛细胞从感觉上皮排出或回缩等退化事件，但未发现再生的证据。
