出生后大鼠螺旋神经节神经元损伤的病理变化

Spiral Ganglion Neurons Pathology in the Postnatal Developing Rats

目的 证实出生后第 2周大鼠螺旋神经节神经元对耳毒性药物敏感。方法 选用出生后 7dSD大鼠36只 ,连续 14d肌注新霉素 ,每天 15 0mg/kg ,分别于停药后 1、7、14、2 8d、3月和 6月各处死 6只。取平行蜗轴的超薄切片 ,透射电镜下观察底回、中回螺旋神经节神经元。结果 大鼠螺旋神经节神经元变性继发于毛细胞和支持结构的损伤 ;停药 1d组存在细胞凋亡现象 ;损伤早期神经元发育延迟 ,损伤晚期神经元由成熟向未分化型改变。结论 出生后第 2周是大鼠螺旋神经节神经元发育的重要阶段 。

Purpose: To confirm that the cochlear spiral ganglion neurons are especially sensitive to the ototoxic drugs in the second week postnatal. Methods: Neomycin was administered to 36 rat pups aged postnatal day 7(divided into 6 groups) at a dosage of 150 mg/kg body weight per day and continued for 14 days. Every 6 animals were respectively sacrificed in 1, 7, 14, 28 days and 3, 6 months after the drug administration. Neuron pathology of the basal and middle turn of the cochlear in the parallel modiular ultrathin sections were observed by transmission electron microscopy. Results: The degeneration of the rat spiral ganglion neurons were following the destruction of the hair cells and the supporting structures. On the early stage of the ototoxicity to the neurons, the development was delayed and the apoptosis of the neurons was observed one day after the drug administration. Later the neurons were changed from maturation to undifferentiated type. Conclusions: The second week postnatal is the critical period to the rat spiral ganlion neurons development, during which the cochlear spiral ganglion neurons are especially sensitive to the ototoxic drugs.