Parietti C, Vago P, Humbert G, Lenoir M
INSERM U254, Université Montpellier I, Faculté de Médecine, Montpellier, France.
Brain Res. 1998 Nov 30;813(1):57-66. doi: 10.1016/s0006-8993(98)00965-2.
Recent studies have shown that an attempt at auditory hair cell neodifferentiation occurs in vivo in the rat organ of Corti after amikacin intoxication during the last stages of cochlear maturation. Atypical cells, with morphological characteristics reminiscent of very immature sensory hair cells, were transiently observed after outer hair cell losses. The aim of the present study was to assess (i) if this attempt at hair cell neodifferentiation was related to the degree of maturity of the organ of Corti and (ii) to characterise morphological and molecular changes in the scarring epithelium. We therefore investigated, using electron and confocal microscopy, morphological and molecular changes in cochleae from rats treated with amikacin at two different periods: from post natal day (PND) 1 to PND 8, when the organ of Corti is very immature; and from PND 30 to 37, when the organ of Corti is morphologically and functionally mature. In both groups, transient atypical cells were observed, attesting that the attempt at hair cell neodifferentiation is not strictly related to the immaturity of the cochlea. The results also suggest that Deiters cells are involved in the appearance of atypical cells, possibly through a transdifferentiation process. Finally, it appears that non-sensory epithelial cells from the outer spiral sulcus progressively colonize the region of pre-existing outer hair cells.
最近的研究表明，在耳蜗成熟的最后阶段，庆大霉素中毒后，大鼠柯蒂氏器在体内会尝试进行听觉毛细胞的新分化。在外侧毛细胞损失后，短暂观察到具有形态特征让人联想到非常不成熟的感觉毛细胞的非典型细胞。本研究的目的是评估：（i）这种毛细胞新分化的尝试是否与柯蒂氏器的成熟程度有关；（ii）表征瘢痕形成上皮中的形态学和分子变化。因此，我们使用电子显微镜和共聚焦显微镜，研究了在两个不同时期用庆大霉素处理的大鼠耳蜗中的形态学和分子变化：从出生后第1天（PND）到第8天，此时柯蒂氏器非常不成熟；以及从PND 30到37天，此时柯蒂氏器在形态和功能上已成熟。在两组中均观察到了短暂的非典型细胞，证明毛细胞新分化的尝试与耳蜗的不成熟并无严格关联。结果还表明，Deiters细胞可能通过转分化过程参与了非典型细胞的出现。最后，似乎来自外螺旋沟的非感觉上皮细胞逐渐占据了先前存在的外侧毛细胞区域。
