Li L, Nevill G, Forge A
Institute of Laryngology and Otology, University College London Medical School, United Kingdom.
J Comp Neurol. 1995 May 8;355(3):405-17. doi: 10.1002/cne.903550307.
In the vestibular and auditory neurosensory epithelia of poikilothermic vertebrates and of birds, damaged sensory "hair" cells are often deleted by extrusion from the apical surface. In contrast, in the adult mammalian auditory epithelium (the organ of Corti), the bodies of damaged hair cells degenerate within the epithelium. To determine whether this apparent difference is species related or is associated with the differing structural organisation of the epithelia, hair cell deletion in the mammalian vestibular end-organs was examined. The structural organisation of these tissues is closer to that of the inner ear epithelia of lower vertebrates than to the organ of Corti. Hair cell loss was induced by chronic, systemic treatment of guinea pigs with the ototoxic aminoglycoside antibiotic gentamicin. The vestibular sensory epithelia were examined at various times after treatment via scanning electron microscopy, thin sectioning, and staining f-actin with fluorescently labelled phalloidin. Two distinct modes of hair cell loss were identified: 1) degeneration of hair cells within the epithelium, which often showed morphological features consistent with those described for apoptosis, and 2) extrusion of intact cells from the apical surface. Neither process caused the formation of obvious lesions through the epithelial surfaces. Expansion of adjacent supporting cells during hair cell deletion resulted in repair that appeared to preserve permeability barriers. There was also no evidence of inflammation accompanying hair cell removal. Thus, with both modes of hair cell loss, it appeared that deletion of hair cells was achieved without disruption of tissue architecture or integrity. This may be important for subsequent repair and regeneration processes to operate.
在变温脊椎动物和鸟类的前庭及听觉神经感觉上皮中，受损的感觉“毛”细胞常通过从顶端表面挤出而被清除。相比之下，在成年哺乳动物的听觉上皮（柯蒂氏器）中，受损毛细胞的胞体在上皮内退化。为了确定这种明显的差异是与物种相关，还是与上皮不同的结构组织有关，研究人员对哺乳动物前庭终器中的毛细胞清除情况进行了检查。这些组织的结构组织与低等脊椎动物的内耳上皮更接近，而与柯蒂氏器不同。通过用耳毒性氨基糖苷类抗生素庆大霉素对豚鼠进行慢性全身治疗来诱导毛细胞损失。在治疗后的不同时间，通过扫描电子显微镜、薄切片以及用荧光标记的鬼笔环肽对肌动蛋白进行染色，来检查前庭感觉上皮。确定了两种不同的毛细胞损失模式：1）上皮内毛细胞的退化，其通常表现出与凋亡描述一致的形态特征；2）完整细胞从顶端表面挤出。这两个过程均未导致上皮表面形成明显的损伤。在毛细胞清除过程中相邻支持细胞的扩张导致了修复，似乎维持了通透性屏障。也没有证据表明毛细胞清除伴随着炎症。因此，对于这两种毛细胞损失模式，似乎毛细胞的清除是在不破坏组织结构或完整性的情况下实现的。这对于后续的修复和再生过程的运作可能很重要。
