Résumé
Objective To establish the different degrees of rat diffuse axonal injury (DAI) model by using a self‐made DAI device .Methods A total of 70 healthy adult clean SD rats were selected and randomly divided into the normal control group (n=10) and DAI group (n=60) ,then the DAI group was randomly subdivided into the group A ,B ,and C ,20 cases in each group .The rat head injury model was prepared by using the self‐made experimental device ,which made the rat head to simultaneously produce instant oversized linear and angular accelerations ,different degrees of rat DAI model ,including mild DAI(group A) ,moderate DAI (group B) and severe DAI(group C) ,were induced by different rotation back and forth ,accelerated movement times under the con‐stant air pressure .The pathological and behavior effect evaluation was performed .Results With the injury degree aggravating ,the time interval of nerve physiological reflex recovery and awakening time in the acute DAI groups were increased (P<0 .05) .The nerve function score after 7 d in the DAI groups was decreased (P<0 .05);the death rates within 14 d after injury in the group A , B and C were 5 .0% ,25 .0% and 50 .0% respectively .With the injury degree aggravating ,the DAI pathological characteristics were more significant .Conclusion This device could effectively establish different injury degrees of DAI animal model .
Résumé
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.