Study On The Rat Model Of Heavy Diffuse Axonal Injury And Time-dependent Expression Of Protein S100β Following Traumatic Brain Injury

Objective: This paper attempts to improve Marmarou' s model of the diffuse brain injury and investigate the time-dependent dynamics of the induction of proteinS100βin different parts of therat' sbrain after it suffers from the diffuse axonal injury. Based on this modification, this paper also provides scientific foundation for the early postmortem and antemortem diagnosis of the diffuse brain injury.Methods: A modified Mararou' s impact device is used to establish the animal model of diffuse axonal injury with severe degree by the impact condition, including180cm×450g, that applies on the rat head. The animal model is evaluated by observing the alterations of nervous system signs and brain tissue morphology in rats after this impact. Immunohistochemistry and auto-image system analysis can determine whether S100βprotein is changed after diffuse axonal injury in cerebral cortex,hippocampus,thalamus and brainstem of rats at he animal's death time: 30min,2h,4h,12h,24h,3d,7d after diffuse axonal injury, and normal rats as control.Results: (1) Compared with control injured rats, the significant alterations of nervous system signs are observed in the rats that are subjected to the severe impact. Histological examination reveals pathologic changes of diffuse axonal injury in all impacted rats. (2) The number of protein S100βpositive cells in the four areas increases significantly followed by a decrease, and then a further increase.Conclusion: (1)A reliable, practical and reproducible rat model of severe diffuse axonal injury have been developed from the modified Mararou's method, and the severe impact180cm×450g, which have produced low animal death rats and resulted in siginificant pathological alteration in injured rat brain, is suitable to investigate the pathophysiological changes following diffuse traumatic brain injury. (2)The present study showed the time-dependent expression of protein S100βis obvious following diffuse brain injury, and suggested S100βis suitable as a marker for brain injury time determination.