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目的研究凋亡是否参与嗅上皮正常生理更替和嗅球摘除后嗅觉神经元死亡而后再生的过程,探讨凋亡与神经元再生的关系。方法应用原位末端标记法和透射电镜观察正常成年大鼠以及摘除嗅球后大鼠嗅上皮16、32、48 h和3、7、30 d时凋亡的出现和改变情况。结果正常成年大鼠嗅上皮中有末端脱氧核苷酸转移酶介导的脱氧三磷酸尿苷缺口末端标记(TUNEL)的阳性细胞(1.93±0.31)个/200μm。摘除嗅球后TUNEL阳性细胞数增加,32 h达峰值(90.9±18.03)个/200μm,以后迅速下降,维持于低水平。透射电镜下见嗅球摘除术后嗅觉神经元出现胞质浓缩、胞核染色质边聚等细胞凋亡的特征性超微结构改变。尚可见少量胞质内出现自噬泡以及除线粒体以外的细胞器扩张,但胞核正常的嗅觉神经元。结论凋亡参与成年大鼠嗅觉神经元生理性更替以及实验性嗅觉神经元死亡和再生的过程。此外,尚存在自噬型和胞质型神经元死亡。
Objective To investigate whether apoptosis is involved in normal physiological turnover of olfactory epithelium and olfactory neuronal death after olfactory bulb removal, and to explore the relationship between apoptosis and neuronal regeneration. Methods The appearance and changes of apoptosis in normal adult rats and olfactory epitheliums 16, 32, 48 h and 3, 7 and 30 d after olfactory bulb removal were observed by in situ end labeling and transmission electron microscopy. Results TUNEL positive cells (1.93 ± 0.31) / 200 μm were detected in normal adult olfactory epithelium by terminal deoxynucleotidyl transferase. The number of TUNEL positive cells increased after olfactory bulb removal, reaching the peak value of (90.9 ± 18.03) / 200μm at 32 h, then decreased rapidly and maintained at a low level. The ultrastructural changes of the apoptosis of olfactory neurons in the olfactory bulb after the olfactory bulb removal were observed by TEM. Can still be seen a small amount of cytoplasmic autophagic vacuoles and in addition to mitochondria organelles outside the expansion, but the normal nucleus olfactory neurons. Conclusion Apoptosis is involved in the physiological turnover of olfactory neurons in adult rats and in the process of experimental olfactory neuronal death and regeneration. In addition, autophagic and cytoplasmic neuronal deaths persist.