Park D L, Girod D A, Durham D
Department of Otolaryngology and the Smith Mental Retardation Research Center, University of Kansas Medical Center, Kansas City, 66160-7380, USA.
Hear Res. 1998 Dec;126(1-2):84-98. doi: 10.1016/s0378-5955(98)00157-9.
It is well documented that damage to the chick cochlea caused by acoustic overstimulation or ototoxic drugs is reversible. Second-order auditory neurons in nucleus magnocellularis (NM) are sensitive to changes in input from the cochlea. However, few experiments studying changes in NM during cochlear hair cell loss and regeneration have been reported. Chicks were given a single systemic dose of gentamicin, which results in maximal hair cell loss in the base of the cochlea after 5 days. Many new hair cells are present by 9 days. These new hair cells are mature but not completely recovered in organization by 70 days. We counted neurons in Nissl-stained sections of the brainstem within specific tonotopic regions of NM, comparing absolute cell number between gentamicin- and saline-treated animals at both short and long survival times. Our data suggest that neuronal number in rostral NM parallels hair cell number in the base of the cochlea. That is, after a single dose of gentamicin, we see a loss of both cochlear hair cells and NM neurons early, followed by a recovery of both cochlear hair cells and NM neurons later. These results suggest that neurons, like cochlear hair cells, can recover following gentamicin-induced damage.
有充分文献记载，听觉过度刺激或耳毒性药物对雏鸡耳蜗造成的损伤是可逆的。巨细胞核（NM）中的二级听觉神经元对来自耳蜗的输入变化敏感。然而，很少有实验报道在耳蜗毛细胞丢失和再生过程中NM的变化。给雏鸡单次全身注射庆大霉素，5天后耳蜗底部的毛细胞损失最大。到第9天时会出现许多新的毛细胞。这些新的毛细胞已成熟，但到70天时其组织结构仍未完全恢复。我们在NM特定音频区域的脑干尼氏染色切片中对神经元进行计数，比较了短期和长期存活时间下庆大霉素处理组和生理盐水处理组动物之间的绝对细胞数量。我们的数据表明，NM前部的神经元数量与耳蜗底部的毛细胞数量平行。也就是说，单次注射庆大霉素后，我们早期会看到耳蜗毛细胞和NM神经元均减少，随后耳蜗毛细胞和NM神经元均恢复。这些结果表明，与耳蜗毛细胞一样，神经元在庆大霉素诱导的损伤后也可以恢复。
