Lustig L R, Leake P A, Snyder R L, Rebscher S J
Department of Otolaryngology, Epstein and Coleman Laboratories, University of California, San Francisco 94143-0526.
Hear Res. 1994 Apr;74(1-2):29-37. doi: 10.1016/0378-5955(94)90173-2.
The effects of chronic intracochlear electrical stimulation on the cochlear nucleus (CN) were studied in eight cats that were neonatally deafened by daily intramuscular injections of neomycin. Profound hearing loss was confirmed in each animal by auditory brainstem response (ABR) and frequency following response (500 Hz) testing. Five of the kittens were implanted unilaterally with a scala tympani electrode array at ages 8-16 weeks. These kittens were stimulated daily for four hours at 2 dB above the evoked ABR threshold, over a period of three months, and subsequently euthanized for histological analysis at 26-32 weeks of age. The three remaining deaf kittens were maintained without stimulation over prolonged periods in order to study the long-term consequences of neonatal deafening, and were euthanized at 66-133 weeks of age. This study compares the CN of these deafened experimental animals and the CN of normal adult cats. Three experimental parameters were examined: CN volume, cross-sectional area of spherical cells in the rostral anteroventral cochlear nucleus (AVCN), and spherical cell density in this same region. The CN in animals that received electrical stimulation showed significant bilateral degenerative changes in all three measured parameters. Total nuclear volume was reduced by 35-36%, spherical cell size was reduced by 20-26%, and spherical cell density decreased by 36-42%, as compared to the normal cat CN. Comparisons were also made in the stimulated animals between CN ipsilateral to the stimulated cochlea and the contralateral, unstimulated CN.(ABSTRACT TRUNCATED AT 250 WORDS)
在八只新生时因每日肌肉注射新霉素而致聋的猫身上，研究了慢性耳蜗内电刺激对耳蜗核（CN）的影响。通过听性脑干反应（ABR）和频率跟随反应（500Hz）测试，证实每只动物均有严重听力损失。五只小猫在8 - 16周龄时单侧植入鼓阶电极阵列。这些小猫在三个月的时间里，每天以高于诱发ABR阈值2dB的强度刺激四小时，随后在26 - 32周龄时安乐死以进行组织学分析。其余三只失聪小猫长期不接受刺激，以研究新生期致聋的长期后果，并在66 - 133周龄时安乐死。本研究比较了这些致聋实验动物的耳蜗核与正常成年猫的耳蜗核。检查了三个实验参数：耳蜗核体积、吻侧前腹侧耳蜗核（AVCN）中球形细胞的横截面积以及同一区域的球形细胞密度。接受电刺激的动物的耳蜗核在所有三个测量参数上均显示出明显的双侧退行性变化。与正常猫的耳蜗核相比，总核体积减少了35 - 36%，球形细胞大小减少了20 - 26%，球形细胞密度降低了36 - 42%。还对受刺激动物中受刺激耳蜗同侧的耳蜗核与对侧未受刺激的耳蜗核进行了比较。（摘要截断于250字）
