He Xiao-Sheng, Xiang Zhang, Zhou Fei, Fu Luo-An, Shuang Wang
Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, PR China.
J Clin Neurosci. 2004 May;11(4):402-7. doi: 10.1016/j.jocn.2004.01.001.
The study investigated morphologically axonal calcium overloading and its relationship with axonal structural changes. Twelve SD rats were divided into an injury and a sham group. The rat model of traumatic axonal injury (TAI) by lateral head rotation was produced. The oxalate-pyroantimonate technique for calcium localization was used to process the rat's medulla oblongata tissues with thin sections observed electron-microscopically for axonal structure and calcium precipitates on it. The axonal damage in medulla oblongata appeared at 2 h post-injury, gradually became diffuse and severe, and continued to exist at 24 hours. At 2 hours, calcium precipitates were deposited on separated lamellae and axolemma, but were rarely distributed in the axoplasm. At 6 hours, calcium precipitates occurred on separated lamellae and axolemma in much higher density, but on axoplasm in extremely small amounts. Some axons, though lacking structural changes of the myelin sheath, sequestered plenty of calcium deposits on their swollen mitochondria. At 24 hours, damaged axons presented with much more severe lamellae separation and calcium deposits. Axonal calcium overloading developed in rat TAI model using lateral head rotation. This was significantly related to structural damage in the axons. These findings suggest the feasibility of using calcium antagonists in cope the management of human DAI in its very early stage.
该研究调查了轴突钙超载的形态学及其与轴突结构变化的关系。将12只SD大鼠分为损伤组和假手术组。制作了通过头部侧转造成创伤性轴突损伤（TAI）的大鼠模型。采用草酸焦锑酸盐钙定位技术处理大鼠延髓组织，制作薄片，用电镜观察轴突结构及其上的钙沉淀。延髓轴突损伤在伤后2小时出现，逐渐变得弥漫且严重，并在24小时时仍然存在。在2小时时，钙沉淀沉积在分离的板层和轴膜上，但很少分布在轴质中。在6小时时，钙沉淀在分离的板层和轴膜上的密度更高，但在轴质中的量极少。一些轴突，虽然髓鞘缺乏结构变化，但在其肿胀的线粒体上积聚了大量钙沉积。在24小时时，受损轴突出现更严重的板层分离和钙沉积。使用头部侧转的大鼠TAI模型中出现了轴突钙超载。这与轴突的结构损伤显著相关。这些发现提示了在人类弥漫性轴索损伤极早期使用钙拮抗剂进行治疗的可行性。
