ULTRASTRUCTURAL OBSERVATIONS ON REGENERATING HAIR CELLS IN THE CHICK BASILAR PAPILLA FOLLOWING AMINOGLYCOSIDE OTOTOXICITY

Newly hatched chicks were injected with so mg/(kg' d) of gentamycin sulfate (GM )for 10 days. After 18st injection, animals were killed on survival days 3,6 .9 and 12. The chick basilar papillae (BP) were observed by transmission electron microscopy (TEM ). The results sho've'Ithat regenerated hair cells were erupted to the hasal membrane surrace in the early phase. The cytoplasm of these regenerated hair cells was heavily stained an contained numerous mitochondria. Afterseveral days, stereocilia appeared. When stereocilis bundles were rormed and cuticular layer was integrated, hasal nerve terminals were round. The results suggested that regenerating hair cells 'veredirectly produced on the hasal membrane surface following gentamycin induced ototoxlcity and thenI,roliferated and developed Into mature normal hair cells.

庆大霉素损害鸡耳蜗后毛细胞再生的超微结构及其与听功能恢复的关系

给实验组鸡按50mg／（kg·d）剂量肌注庆大霉素共10d后，间隔1、3、6、9和12d对实验组和对照组鸡耳蜗电位（Ap）及听觉脑干诱发电位（ABR）进行测定，随后处死动物，用透射电镜（TEM）和扫描电镜观察鸡基底乳头（BP）毛细胞再生的超微结构和过程，结果可见毛细胞再生来源于Bp表层扁平状或立方形上皮细胞，在早期再生毛细胞胞质密度高，含有大量的线粒体，随后静纤毛长出，细胞核出现，表皮极发育成熟时静纤毛束形成，其毛细胞底部的神经末梢已长出，此时伴有Ap和ABR阈值的恢复。说明再生毛细胞形态成熟时已具有听觉功能的恢复，再生毛细胞在受损耳蜗听功能的恢复过程中起主要作用。

正常雏鸡基底乳头的扫描电镜观察

对１０只出壳后３～７天的雏鸡的基底乳头进行扫描电镜观察及ＡＢＲ阈值测定，发现雏鸡基底乳头由近及远逐渐增宽，毛细胞数逐渐增多，毛细胞表面的纤毛逐渐变长，纤毛间的长短差异逐渐变小，表皮板直径由大到小。毛细胞表面呈较为规则的六边形或五边形，细胞间均由支持细胞表面突起分隔开来。据此推测鸡听乳头可能具有周围分析器功能，而从表面结构上是难以区分高、矮细胞的。