Laurent C, Anniko M, Hellström S
Department of Oto-Rhino-Laryngology, University Hospital, University of Umeå, Sweden.
Acta Otolaryngol. 1991;111(3):506-14. doi: 10.3109/00016489109138376.
Hyaluronan (HYA) in 1% solution was instilled into the round window (RW) niche of rats (n = 6) prior to perforating the round window membrane (RWM). Cochlear functioning and structure were then monitored by recording auditory brainstem responses (ABRs) at 2-31.5 kHz and by scanning electron microscopy. Perforation of the RWM alone (n = 6) resulted in immediate loss of ABR thresholds between 6 and 31.5 kHz in 2 of 6 animals. Similar results were obtained after instilling HYA into the RW niche and subsequent RWM perforation (n = 6). After 2 months, ABR thresholds were recorded at all frequencies in the HYA-treated animals, whereas in 2 of the controls no ABR thresholds could be elicited at 20 and 31.5 kHz. However, in both treatment groups the mean ABR thresholds and mean latencies for wave II at the ABR threshold returned to the pre-surgical (normal) range after 2 months. With respect to the cochlear morphology the results in both treatment groups were also alike including minor structural changes in hair cell stereociliae but no loss of hair cells. It is concluded that HYA, when instilled into the middle ear with the inner ear opened, is free from cochlear otoxicity.
在穿孔圆窗膜（RWM）之前，将1%溶液中的透明质酸（HYA）滴入大鼠（n = 6）的圆窗（RW）龛中。然后通过记录2 - 31.5kHz的听性脑干反应（ABR）以及扫描电子显微镜来监测耳蜗功能和结构。仅RWM穿孔（n = 6）导致6只动物中有2只在6至31.5kHz之间的ABR阈值立即丧失。在将HYA滴入RW龛并随后进行RWM穿孔后（n = 6）也获得了类似结果。2个月后，记录了接受HYA治疗动物所有频率的ABR阈值，而在对照组中有2只在20和31.5kHz时无法引出ABR阈值。然而，在两个治疗组中，2个月后ABR阈值的平均值以及ABR阈值处波II的平均潜伏期均恢复到术前（正常）范围。关于耳蜗形态，两个治疗组的结果也相似，包括毛细胞静纤毛的轻微结构变化，但没有毛细胞损失。得出的结论是，当在内耳开放的情况下将HYA滴入中耳时，它没有耳蜗毒性。
