家兔耳蜗柯替氏器的扫描电镜观察

A SEM STUDY OF STRUCTURE IN THE RABBIT COCHLEAE

在麻醉状态下,取5只家兔的5个完整的耳泡,剔除中耳和外耳的硬骨及听小骨,将耳蜗用2%戊二醛磷酸盐缓冲液冲洗并固定8小时(4℃),随后投入10%EDTA二钠溶液中脱钙10天。再将耳蜗外骨壳磨除并摘去残余骨。经1%OsO_(4)溶液后固定、脱水、临界点干燥、真空喷金等步骤后,于扫描电镜下观察。家兔耳蜗呈两周半螺旋状,其蜗轴高约3.5mm,柯替氏器位于骨螺旋板外方的基底膜上。在蜗顶可见4排外毛细胞,而耳蜗其他部位通常仅有3排;内毛细胞为1排。每一簇外听毛在高倍镜下略呈W形,由93~114根纤毛组成;每簇内听毛呈半弧形,约由50根纤毛组成。顶周的听毛比基底周的稍长。本文计数了柯替氏器上6种细胞的数量并测量了细胞的长和宽。此外,待家兔死亡后1、2、4小时,对3个不同时间取材固定的另外3只耳蜗作扫描电镜观察,发现于死后4小时才加以固定的柯替氏器听毛多呈倒伏状。表明耳蜗的取材与固定应尽可能在死后4小时内完成,以便保持组织结构的生前状态。本文还比较了家兔、豚鼠和人耳蜗柯替氏器的异同。

Five inner ears were removed from five rabbits under aneasthesia.The hard,thick bones of outer and middle ears were trimmed off,and the auditory ossicles were taken away.The cochleae were fixed with 2%glutaraldehyde in phosphate buffer for eight hours,then they were decalcified in 10%EDTA-2Na solution for ten days,and the softened shells of the cochleae were stripped off,and post-fixed in 1%OsO_(4)for an hour,dried at critical point,coated with gold,and observed under SEM.The rabbit cochlea shows two and a half turns,the modiolus is about 3.5mm high,and the organ of Corti lies on the basilar membrane of the spiral lamina.The outer hair cells usually form three parallel rows on the middle and basal turns but occasionally four rows on the top half turn.The inner hair cells form only a single row.Every bunch of the outer hairs consists of about 93-114 stereocilia which together show a"W"shape.Every bunch of inner hairs has about 50 cilia which together show an arch shape.The cilia on the top turn are longer than those on the base.The length and width of the inner and outer hair cells and four other kinds of cells were measured according to photos,and the numbers of these kinds of cells were estimated.Other three cochleae fixed at the time of 1,2 or 4 hours after death were also observed.In the cochlea fixed four hours after death,the majority of the auditory hairs were found fallen down,which means the fixation of cochlea should be carried out within less than four hours after death.Some of the structural similarities and differences of cochleae among rabbit,human being and guinea pig were also compared in this paper.