Lenoir M, Vago P
INSERM U. 254 et université Montpellier, France.
C R Acad Sci III. 1996 Apr;319(4):269-76.
Postnatal rats were treated with amikacin during the period of cochlear supra-normal sensitivity to ototoxic antibiotics, i.e. from day 9 to day 16 when the organ of Corti is achieving its maturation. Scanning and transmission electron microscopies were used to evaluate morphological changes in the organs of Corti at different post-treatment periods, up until postnatal day 90. A massive loss in outer (OHCs) and inner (IHCs) hair cells was observed from as early as day 17. A prominent feature in the apical part of cochleas at days 21 and 35 was the transient presence of small atypical cells in the region of pre-existing OHCs. These atypical cells did not have the appearance of degenerating OHCs, but had tuffs of microvilli reminiscent of nascent stereociliary bundles. A second striking observation was the presence of pear-shaped cells in the place normally occupied by IHCs. These cells had neither cuticular plate nor stereocilia, but their basal pole was contacted by both afferent and efferent fibers, as in the early stages of IHC maturation. Such efferent contacts are very rare in the adult cochlea. These findings, not previously reported in antibiotic poisoned cochleas of adult animals, suggest that an attempt at sensory cell neodifferentiation occurs in vivo in the developing organ of Corti intoxicated with aminoglycoside antibiotics.
在耳蜗对耳毒性抗生素超敏的时期，即从出生后第9天到第16天（此时柯蒂氏器正在成熟），对新生大鼠使用阿米卡星进行处理。利用扫描电子显微镜和透射电子显微镜评估处理后不同时期直至出生后第90天柯蒂氏器的形态变化。早在第17天就观察到外毛细胞（OHCs）和内毛细胞（IHCs）大量损失。在第21天和第35天，耳蜗顶部的一个显著特征是在先前存在的外毛细胞区域短暂出现小的非典型细胞。这些非典型细胞没有退化外毛细胞的外观，但有类似于新生静纤毛束的微绒毛簇。第二个显著观察结果是在通常由内毛细胞占据的位置出现梨形细胞。这些细胞既没有角质板也没有静纤毛，但它们的基极与传入和传出纤维接触，就像在内毛细胞成熟的早期阶段一样。这种传出接触在成年耳蜗中非常罕见。这些在成年动物抗生素中毒耳蜗中以前未报道过的发现表明，在被氨基糖苷类抗生素毒害的发育中的柯蒂氏器中，体内发生了感觉细胞新分化的尝试。
