耳蜗外毛细胞静纤毛束变异的判定标准与抵抗耳中毒的能力

Variant of Stereociliary Bundles of Cochlear Outer Hair Cell and it Relatioship With Ototoxicity on Gentamicin

目的建立耳蜗外毛细胞(OHC)静纤毛束变异的判定标准,观察毛细胞静纤毛束变异对庆大霉素耳中毒的抵抗能力。方法对豚鼠测定听性脑干反应(ABR)阈值和畸变产物耳声发射(DPOAE)振幅后,选取静纤毛束正常和变异豚鼠各5只,连续肌注庆大霉素(grntamicin,GM)12d后,测定ABR阈值,扫描电镜观察耳蜗外毛细胞静纤毛束变异情况,耳蜗铺片计数毛细胞的损失数。结果耳蜗底回第一排外毛细胞静纤毛束转位超过45°、“W”变形数超过10%,作为豚鼠耳蜗外毛细胞静纤毛束变异的判定标准。5只静纤毛变异豚鼠GM注射12d后平均ABR阈值51.0±8.76dBSPL,外毛细胞损失约16%～39.96%,柯替器受损程度较轻;而外毛细胞(OHC)正常豚鼠GM注射12d后ABR阈值上升到58.4～100dBSPL,OHC基本消失,柯替器毛细胞破坏较为严重。结论耳蜗外毛细胞静纤毛束变异豚鼠较OHC正常者对GM中毒具有较大的耐受能力。

Objective To observe the difference between the outer hair cell loss and auditory function of the normal cochlea outer hair cell and variant stereociliary bundies in guinea pigs with ototoxicity of gentamicin.Methods Auditroy brainstem responses(ABR) and otoacoustic emission of distortion products(DPOAE) were assayed to 5 normal and variant guinea pigs,animals were given intramuscular in jection of gentamicin(GM 80 mg·kg -1 ·d -1 ) for 12 consecutive days and tested with ABR and DPOAE.The cochlear hair cells were observed by scanning electron microscope and light microscope.Results The rotation of stereociliary bundies in first ran OHL was begond 45° and the variant of ‘W’ was more than 10% might be a marker to jadge the variant stereociliary bundles of OHC in guinea pigs.The avevage ABR threshold was 54.3±7.5 dB SPL of variant stereociliary bundles in 5 guinea pigs following GM treatment, cochlear hair cell loss was about 16%～39.9%.The theshold of normal stereociliary bundies guinea pigs was increased to 58.4～100 dB SPL,cochlea hair cell was destroied seriously.Conclusion The animal of variant stereociliary bundles was high tolerance ability as compared with normal animals to GM treatment which were due to the most out hair cell loss.