阿米卡星致聋大鼠鼓阶壁上皮超微结构的改变

目的观察大鼠经氨基糖苷类抗生素硫酸阿米卡星注射致聋后,耳蜗鼓阶壁上皮超微结构的改变;探索干细胞移植进入鼓阶后,干细胞在内耳发生迁移的结构基础。方法出生7天的SD大鼠30只,随机分为实验组(20只)与对照组(10只)。实验组连续7天经腹腔按照200mg/kg/day的剂量腹腔注射硫酸阿米卡星注射液;对照组注射相同体积的生理盐水。在停药后0天、7天、14天、21天、28天取耳蜗组织,随机选择其中一侧行扫描电镜观察耳蜗底回鼓阶的上皮的变化,另一侧耳蜗做冰冻切片、HE染色进行形态学观察。结果腹腔硫酸阿米卡星在引起大鼠耳聋的同时,鼓阶上皮细胞的超微结构也随着时间发生变化,上皮细胞经历了炎性渗出、细胞间隙扩大和上皮细胞恢复的形态变化过程。结论氨基糖带类抗生素硫酸阿米卡星除引起内耳柯蒂氏器的细胞死亡之外,还可以引起附着在内耳鼓阶骨壁的上皮细胞形态发生超微结构的改变。这种变化规律,有可能成为通过鼓阶进行干细胞移植的结构基础,并且为经耳蜗鼓阶移植干细胞治疗内耳疾病的时间提供参考。

Ultrastructural changes of epithelium on wall of scala tympani in rats with Amikacin induced hearing loss

Objective To investigate ultrastructural changes of epithelium attached to the bony wall of scala tympani in rat cochleae after amikacin sulfate administration and the structural basis for migration of transplanted mouse embryonic stem cells. Methods Rats were randomly divided into an experiment group (n=20) and a control group ( n=10 ) .For rats in the experiment group, amikacin sulfate was injected hypodermically at a dose of 200 mg/kg/day for seven days, while rats in the control group received physiological saline of the same volume instead. The cochlea was removed on 0d, 7d, 14, 21d and 28d after amikacin administration was finished. Cochlea on one randomly selected side was prepared for SEM observation and the other cochlear for HE examination. Results Amikacin sulfate administred to rats induced hearing loss. Epithelia on the bony wall of scala tympani underwent serial ultrastructural changes, including inflammatory exudation and increase of the intercellular spaces, which recovered in a time dependent manner. Conclusion Besides injury and loss of the hair cells in the Organ of Corti, amikacin sulfate treatment can also induce ultrastructural changes on the bony wall of scala tympani which may be the structural base for transplanted stem cell migration from scala tympani in the cochlea. Our results show the time window for inner ear stem cell therapy after ototoxic drugs injury.