新霉素致发育中大鼠毛细胞损伤的电镜观察

目的应用扫描电镜研究氨基甙类抗生素导致出生后发育过程中大鼠耳蜗毛细胞的损伤病理变化。方法７天龄ＳＤ大鼠肌肉注射８０ｍｇｋｇ－１ｄ－１新霉素连续８天，停药后７天处死动物制备样本进行扫描电镜观察。结果新霉素可造成出生后发育过程中的耳蜗毛细胞严重损伤，表现为底回和钩回三排外毛细胞全部损伤缺失，损伤病变累及顶回的外毛细胞，底回和钩回的内毛细胞出现纤毛脱落和细胞损伤丢失；外毛细胞损伤缺失的部位由顶部具有微绒毛的多边形细胞取代，该细胞形态与胚胎发育早期的毛细胞相似；毛细胞损伤区域未发现再生的毛细胞。结论出生后发育过程中大鼠耳蜗毛细胞对氨基甙类抗生素的敏感性较高，表面有微绒毛的多边形细胞在毛细胞损伤区域出现提示听觉感觉上皮细胞有再生的倾向。

SEM Observations of the Cochlear Hair Cell Pathology Induced by Neomycin Ototoxicity During Postnatal Development in Rats

Objective To study cochlear hair cell pathology induced by Neomycin ototoxicity during postnatal development in rats by means of scanning electron microscopy(SEM). Methods Seven-day-old rats were treated intramuscularly with Neomycin 80 mgkg1d-1 for 8 successive days and were allowed to survive seven days before sacrifice and preparation for observation by SEM. Results Neomycin induced severe damage on cochlear hair cell during postnatal development of rats.Three rows of outer hair cells (OHCs)in the basal turn and hook region were lost and OHCs in apical turn were also affected.The disoriented or partly disappeared stereocilia of inner hair cell(IHC)and loss of IHC were observed in the basal turn and hook region.Epithelium of the former OHC region was replaced by polygonal cells with a tuft of microvilli at their apical surface,which were similar to the early stage of embryonic development of cochlear hair cells.Regenerated hair cells were not found in the damaged region of the sensory epithelia. Conclusion Cochlear hair cells were more sensitive to the ototoxic effects of Neomycin during postnatal development in rats.The polygonal cells toped with a tuft of microvilli appeared in the damaged region indicated that auditory receptors showed an attempt to regenerate.