Igarashi Y, Oka Y
Department of Otolaryngology, St. Marianna University School of Medicine, Kawasaki, Japan.
Arch Otorhinolaryngol. 1988;245(4):210-7. doi: 10.1007/BF00463929.
Our previous studies have shown that the disinfectant chlorhexidine gluconate (CH) has an ototoxic effect on the cochlea following its topical application in the middle ear space. The purpose of the present investigation was to demonstrate morphologically if CH also has the potential to injure the vestibular organs in the inner ear and, if so, what structures are most strongly damaged. Nine cats were used for the study. The drug dose of CH and the number of its applications to the middle ear were the same as used in our previous study to produce middle ear injuries. In the 2% CH group of cats pronounced degeneration was found in afferent nerve endings and both types of sensory cells. These nerve terminals showed edematous dilatations and contained degenerated mitochondria. Highly dark-stained degenerated mitochondria were distributed in the sensory cells and the afferent nerve terminals in the 0.05% CH group, but these degenerative changes were much less than in the 2% CH group. No otolithic crystals or synaptic vesicles could be seen in the 2% CH group. The results from this study showed that CH as a disinfectant has an ototoxic effect on the labyrinthine vestibule in which the sensory cell-nerve ending complex is affected as the main target. Even when used in dilute clinical concentrations, vestibular disturbances are a likely complication if the drug solution flows into the middle ear through a perforated eardrum.
我们之前的研究表明，消毒剂葡萄糖酸氯己定（CH）经中耳局部应用后，会对耳蜗产生耳毒性作用。本研究的目的是从形态学上证明CH是否也有可能损伤内耳的前庭器官，如果是，哪些结构受损最为严重。本研究使用了9只猫。CH的药物剂量及其应用于中耳的次数与我们之前用于造成中耳损伤的研究相同。在2%CH组的猫中，发现传入神经末梢和两种类型的感觉细胞均有明显退变。这些神经末梢出现水肿性扩张，且含有退变的线粒体。在0.05%CH组中，感觉细胞和传入神经末梢中分布着高度深染的退变线粒体，但这些退变变化远少于2%CH组。在2%CH组中未见耳石晶体或突触小泡。本研究结果表明，作为消毒剂的CH对迷路前庭具有耳毒性作用，其中感觉细胞 - 神经末梢复合体是主要受影响的靶点。即使在临床稀释浓度下使用，如果药物溶液通过鼓膜穿孔流入中耳，前庭功能障碍也很可能是一种并发症。
