脑弥漫性轴索损伤实验装置的研制及动物模型的建立

目的 自制一种脑弥漫性轴索损伤(DAI)装置并成功建立DAI动物模型.方法 自制头颅瞬间旋转损伤装置,使大鼠头颅在瞬间(<3ms)旋转90°造成剪切损伤.观察损伤后大鼠的生命体征及行为学改变;于伤后2、6、12、24、36、72h及10d分别处死损伤组动物,制备脑石蜡切片,行镀银及HE染色,光镜下观察神经轴索变化.结果 伤后大鼠均即刻出现原发昏迷,其中2只于损伤后20min内死亡,余持续时间1-30min不等;伤后大鼠呼吸节律紊乱,瞳孔对光反射减弱或消失,醒后均有程度不等的反应性下降,肢体活动迟缓;肉眼可见广泛蛛网膜下腔出血或脑室出血;光镜下可见皮髓交界区、胼胝体区、脑干、小脑白质等部位的神经轴索有不同程度的肿胀、断裂、轴索球形成,后期有小胶质细胞增生,局部呈巢样聚集.结论 本装置能造成大鼠脑DAI,且具有简便、可控、确切的特点,适合进行中、小型动物DAI模型的实验研究.

Rat diffuse axonal injury model constructed by a new experimental facility

Objective To design a new experimental facility to induce rat diffuse axonal injury model. Methods Rat diffuse axonal injury was induced by a new experimental facility,which was developed to let the rat head spin 90 degree at the moment to cause shearing injury.Vital sign and behavior of rat were measured simultaneously.The rats were sacrificed at 2 h,6 h,12 h,24 h,36 h,72 h and 10 d after injury,respectively,and the brain tissues were removed to prepare paraffin section.Then silver staining and HE staining were conducted to investigate changes of axonal fibers. Results There were unconsciousness,respiratory rhythm disturbance and hyporeflexia of pupil light reflex immediately after injury,and reactiveness decrease and activity retardation still existed even after resuming consciousness.At anatomical scene,subarachnoid hemorrhage or cerebroventricular haemorrhage were widespread.At an early stage,there were swelling,collapse,and axonal retraction ball formation at cortico-medulla junction,callosum,brainstem,and cerebellar white matter under microscope.But at the later stage,gitter cell proliferation and nest-like aggregation were major pathophysiological changes at focal brain tissue. Conclusion The new experimental facility is suit able to be used to induce rat diffuse axonal injury,since it is convenient,controlable,and precise.