灰鼠疆孔内听神经纤维的定量观察

Quantitation of nerve fibers in habenula perforata in chinchilla

目的为了观察正常灰鼠和卡铂（Ｃａｒｂｏｐｌａｔｉｎ）耳中毒灰鼠耳蜗单个疆孔（ｈａｂｅｎｕｌａｐｅｒｆｏｒａｔａ）内的神经纤维数量。方法１２只灰鼠中６只按１００ｍｇ／ｋｇ腹腔注射卡铂２次，６只作正常对照，３个月后处死，沿蜗轴平面作半薄切片，甲苯胺蓝－美蓝染色后光镜观察，组间统计学比较采用ｔ检验。结果正常灰鼠的神经纤维数量在耳蜗不同部位有所不同，其中在底回起始段每个疆孔中通过９３．７±１２．２（ｘ±ｓ，下同）根神经纤维，底回末段为１８１．５±３０．４，第二回中段为１２９．７±２７．８，顶回中段为７５．８±１３．２。应用加倍大剂量卡铂将内毛细胞和Ｉ型螺旋神经元全部破坏后，疆孔内残存的神经纤维数仅占正常值的七分之一。结论疆孔内七分之六的神经是支配内毛细胞的Ｉ型神经元。

Objective To examine the number of nerve fibers in the habenula perforata of the cochlea in normal and carboplatin treated chinchillas. Methods Three months following administration of carboplatin (100 mg/kg ×2), six carboplatin treated animals, together with 6 controls, were sacrificed, prepared for semi thin sectioning of the cochlea. The sections were stained with toluidine blue and basic fuchsin, examined under a light microscope and photographed. Results In normal chinchillas, the numbers of the nerve fibers in each habenula opening varied across the cochlea, with 93.7 ±12.2( ±s ) fibers at the hook, 181.5±30.4 at the upper of basal turn, 129.7±27.8 at the second turn and 75.8±13.2 at the apical turn. In cochlear devoid of type I ganglion cells and inner hair cells as a result of carboplatin treatment, only one seventh of the fiber population remained.Conclusion Approximately six seventh of the nerve fibers in the habenula are type I afferent axons that innervate the inner hair cells. The remaining fibers are type II afferents and surviving efferents.