迷路内积血致感音神经性聋的实验研究

Hematocele in Labyrinth Causing Sensorineural Hearing Loss in Guinea Pigs

目的观察迷路内积血病变特征,为其导致感音神经性聋的病因学理论提供实验基础。方法采用豚鼠自体抗凝微量血液行鼓阶内注射,分别于术前和术后不同时间测试听神经复合动作电位、耳蜗微音电位、颞骨MRI扫描、耳蜗火棉胶切片光镜观察、内耳超薄切片和透射电镜观察。结果鼓阶内灌注不同量血液的2个实验组术后不同时间均出现感音神经性聋,以术后第7天较为严重;听力损失特点表现为低频(0.5kHz)最为显著,中频(2kHz)次之,高频(8kHz)较轻;术后1个月时听功能无明显好转。两实验组间听力损伤程度和类型于术后各时间均无显著性差异。MRI T1加权可显示迷路内积血的高信号,且迷路内的积血在术后不同时间段有不同的形态学特征:由最初的积血(术后第1天)演变成积血与纤维网状样结构共存(术后第7天),到最后(术后30天)仅存纤维网状样结构。透射电镜显示部分动物的外毛细胞内线粒体呈水肿或空泡样变,胞浆稀疏,纤毛倒伏。结论迷路内积血可引起豚鼠感音神经性聋,听力损失以低频区更为严重。不同积血量引起的听力损失程度和类型无显著差异。MRI可良好显示内耳积血不同病程阶段在迷路内的分布与变化。迷路内积血最终可被吸收。

Objective To investigate whether the hematocele in perilymphatic space will affect the animal＇s hearing function and induce the pathological morpholagic change or not. Methods The blood with anticoagulant, which was taken from the guinea pig itself, was injected into the scala tympani through the opening at cochlear basal turn bone wall. Before and after oparation, the EcochG was examined. The redistribution of the infected blood in the labyrinth was observed by magnetic resonance imaging （MRI） in different intervals after infecting blood into scala tympani. The change of the injected blood in perilymphatic space and the pathological morphologic changes of labyrinth was observed under light microscopy in three different stages after surgery （ 1 day, 7 days, and 30 days）.The ultramicroscopic pathological changes of Corti organs, spiral ganglions and the strial vascularis were observed under transmission electronic microscopy. Results After injecting blood into scala tympani, the guinea pigs showed different degrees of hearing loss in two experimental groups. There was no difference between these two groups in the type and level of hearing loss. There, was high signals in the labyrinth on enchanted T1 - weighted MRI after injecting blood into perilymphatie space. Conclusion The hematocele in the labyrinth can damage the guinea pig＇s hearing. There is no difference between the two different amount blood （5 μl and 10μl） experimental groups in the type and levels of hearing loss. The hematocele in perilymphatie space can induce the inflammatory reaction in perilymphatic and endolymphatic cavities. The injected blood will be absorbed and/or change into fibrous reticulation.