经鼓阶胚胎干细胞内耳导入的初步观察

The observation of embryonic stem cells transplantated into the inner ear through scala tympani

目的观察未经体外诱导的胚胎干细胞(embyonic stem cells,ESC)导入听力正常大鼠内耳的可行性以及导入后的存活和分布情况,为ESC内耳移植治疗由毛细胞缺失导致的感音神经性耳聋提供实验基础和理论依据。方法5～6周龄Wistar大鼠,10只,右耳为实验耳:经鼓阶打孔法植入带有绿色荧光蛋白(EGFP)的ESCs;左耳为对照组,不实施手术。术前1周与术后即刻行听性脑干反应(ABR)检查,取双侧耳蜗做冰冻切片,观察ESCs植入内耳后存活和分布情况。结果术后动物存活8只,麻醉效果好无干扰完整测完ABR动物5只。鼓阶打孔途径导入耳蜗的ESCs大部分于鼓阶聚集悬浮,少数可在鼓阶基底膜嵴和鼓阶外侧壁处贴壁;未在柯替器等中阶部位中发现有ESCs的分布。ABR检测结果显示鼓阶打孔途径导入方法对大鼠听力影响较小。结论胚胎干细胞可经耳蜗底转鼓阶打孔途径导入耳蜗,干细胞在内耳成功存活,并且对内耳损伤小,因此,它可以作为内耳细胞移植的重要方式。

Objective To observe the feasibility of transplanting undifferentiated embyonic stem cells （ESCs） into the inner ear of normal rat and the distribution of the survival cells, and to provide experimental basis and theoretical for the treatment of sensorineural hearing loss caused by hair loss. Methods Ten Wistar rats aged 5 - 6 weeks were used. ESCs Canying the green fluorescent protein（EGFP） were transplanted into the scala tympani of the right ear while the left ear was drilled a whole in the lateral wall of the scala tympani. To observe the the survive and distribution of the delivered cells, auditory brainstem response （ABR） thresholds were determined before and after the surgery, and than the animals were sacrificed for section specimens. Results Eight of the experiment animals survived, but only 5 rats received perfect ABR examination without interference. Most of the grafted ESCs transplanted through scala tympani were aggregated into clumps and suspended in the scala tympani, while a few of them adherented in the basement membrane and the lateral wall of scala tympani, but none of them migrated to the scala medium. Datas of ABR indicated minimal hearing disturbance by the injection procedure. Conclusions ESCs can be transplanted into inner ear via micro-injection through basal turn of scala tympani, in which the grafted cells can survive in the inner ear with minimal disturbance to it, therefore it is an important way for inner ear cell transplantation.