脑干枪弹伤的电镜观察

Electron microscopic observation of the gunshot wounds of the truncus cerebri

目的 研究脑干枪弹伤的超微改变及其分子水平的致死机理。方法 用一例颅外损伤与2例头部枪伤作对比,于死亡后25min切取其脑干部组织块,相当于弹道处主要取自中脑被盖部与脑桥的被盖部和延脑的第四脑室底深部灰质部的组织,进行透射电镜及扫描电镜观察。结果 (1)脑内的枪弹伤病理改变包括烧灼伤、冲击和压力伤等。(2)枪弹伤虽在中脑而病理改变波及整个脑干。(3)损伤特点是神经轴突最广泛和损伤严重,神经胶质纤维次之,神经元受损又次之。(4)轴突烧灼伤表现髓鞘、轴浆及其内线粒体浓缩、变性,轴浆、轴索水肿;冲击、压力伤呈现轴突扭曲、变形、融合、挤压、缺损、破(断)裂及错位,轴浆内容外流或缺失,轴索内线粒体、神经微丝和微管偏向一侧位等。结论 脑干网状结构严重广泛性神经轴索损伤可能与致死有着最重要关系。

Objective To study the ultrastructural changes of gunshot wounds at the brain stem and the cause of the death. Method A case died of the head injury and two cases died of gunshot wounds of the brain stem were studied. Brain stem tissues were taken 25 min after death. Tissue blocks from the tegmentum of the midbrain and the pons as well as the gray matter of the medulla oblongata in the deep portion of the base of the fourth ventricle were taken and were examined with ultramicroscopy and scanning electron microscopy. Results (1) The gunshot wound injuries inside the brain including burn and injuries caused by punch and pressure; (2) Although the primary gunshot wounds were located at the midbrain, the pathological changes extended to the whole brain stem; (3)The injuries of the axons and the nerve cells were more severe and extensive than those of the glia fibers. (4)The changes of the burn included condensation and degeneration of the myelin sheath and axonal cytoplasm, especially the mitochondria as well as edema of the myelin sheath and the axonal cytoplasm. The punch and pressure injuries included the torsion, deformation, fusion, compression, breach, torn and displacement of the axons with loss of cytoplasm as well as the deviation of mitochondria, micro ?neuro - fibrils and micro - tubules in the axons. Conclusion The severe and extensive injuries of the axons of nerve fibers in the brain stem might play an important role in the cause of death of gunshot.