庆大霉素对内侧橄榄耳蜗传出神经毒性作用的形态学观察

目的观察庆大霉素慢性耳中毒前后蒙古沙鼠内侧橄榄耳蜗（ｍｅｄｉａｌｏｌｉｖｏｃｏｃｈｌｅａｒ，ＭＯＣ）传出神经的形态改变及其与毛细胞损害的关系，以探讨ＭＯＣ传出神经在氨基糖甙类抗生素慢性耳中毒中的重要性。方法采用改良的乙酰胆碱酯酶组化染色和甲苯胺蓝苏木素染色法，全耳蜗铺片观察健康对照组和庆大霉素组耳蜗ＭＯＣ传出神经和外毛细胞（ｏｕｔｅｒｈａｉｒｃｅｌ，ＯＨＣ）的分布特征，并测量耳蜗ＭＯＣ传出神经纤维、末梢及ＯＨＣ的数量。结果停药后３周出现耳蜗ＭＯＣ纤维和末梢损害，损害程度随观察时间延长而加重，１１周最明显，且损害部位主要在耳蜗底回，与毛细胞损害的特征一致。结论耳蜗ＭＯＣ传出神经可能在庆大霉素慢性耳中毒时ＯＨＣ的损害中起重要作用。

Morphological observations of the medial olivocochlear efferents in gerbils with chronic gentamicin ototoxicity

Objective To determine the possible involvement of the medial olivocochlear efferents (MOC) in chronic aminoglycoside ototoxicity, the morphological changes of the MOC efferents in the cochlea of Mongolian gerbils and their correlations with the impairment of the outer hair cells (OHCs) were observed. Methods The animals were given gentamicin in a dose of 150 mg/kg a day for 10 days. The distributions and densities of the MOC efferents were examined using the modified histochemical staining for acetylcholinesterase (AChE) and the numbers of OHCs were numerated with toluidine blue and Ehrlich haematoxylin staining on the surface preparation. Results Significant damage to the MOC fibers and terminals as well as OHCs was noted in the basal turn of the cochlea, especially in those animals examined in 7th and 11th week after the gentamicin administration. The site of the greatest impairment of OHCs was consistent with that of the MOC efferents. Conclusion The results suggested that damage to the MOC efferents might play an important role in gentamicininduced impairment of OHCs.