大鼠弥漫性轴索损伤后神经元超微结构的观察研究

Uitrastructural changes of neurons in rats with diffuse axonal injury

目的探讨大鼠弥漫性轴索损伤（DAI）后神经轴索与神经元胞体超微结构特征与动态变化规律。方法选用32只SD成年大鼠，其中对照组4只，损伤组28只。采用自制头颅旋转致伤装置，将损伤组大鼠头颅在冠状面绕脑组织中心逆时针旋转90。造成剪力伤，于伤后30min、2h、6h、12h、24h、36h、72h分批处死大鼠并取脑组织制作成电镜样品，于透射电镜下观察。结果损伤组大鼠伤后可见轴索肿胀、断裂等形态学改变：各组轴索受损程度计分分别与对照组比较，结果显示损伤组受损程度显著重于后者（P〈0．05）。神经元胞体的形态学改变在伤后2h开始出现，伤后各组受损程度计分分别与对照组比较，30min组和72h组与对照组无显著性差异（P〈0．05），其余各组受损程度显著重于对照组（P〈0．05）。结论DAI是原发损伤与继发损伤共同作用的病理生理过程，继发损伤加重轴索损伤，引起相应的临床症状；轴索损伤与神经元胞体的受损机制不同，病理过程不同步。

Objective To observe the ultrastructural characteristics and dynamic changes of neurons in rats with diffuse axonal injury （DAI）. Methods Thirty-two SD rats （4 for sham operated group, 28 for injury group） and a self-made rotating injury device were used. The heads of rats in injury group were rotated immediately in the coronal plane by 90° to the anticlockwise direction. The injured rats were killed at 30 min, 2, 6, 12, 24, 36 and 72 h post injury （4 rats each time） respectively. Tissue slides of the brain were made and observed under transmission electron microscope. Resdts The sign of various severity of axonal swelling and discontinuity was observed at early stage （30 min） in injury group, the scores of damage degree were tested in rank sum test, and the scores suggested that the damage degree of axon in injury group was more severe than that in sham group （P〈0.05）. Damage degree ofpericaryon in injury group was more severe than that in sham group （P〈0.05） except 30 min group and 72 h group （P〉0.05）. Conclusions DAI was caused by primary injury and insecondary injury in common, insecondary injury aggravates axonal injury, which causes clinical symptom accordingly. Mechanism of axonal injury is different with that of cellular injury, and their progress of pathology is different.