Establishment of a blunt impact-induced brain injury model in rabbits

【Abstract】 Objective: To establish an animal model to replicate the blunt impact brain injury in forensic medicine. Methods: Twenty-four New Zealand white rabbits were randomly divided into control group (n=4), minor injury group (n=10) and severe injury group (n=10). Based on the BIM-Ⅱ Horizontal Bio-impact Machine, self-designed iron bar was used to produce blunt brain injury. Two rabbits from each injury group were randomly selected to monitor the change of intracranial pressure (ICP) during the impact-ing process by pressure microsensors. Six hours after injury, all the rabbits were dissected to observe the injury mor-phology and underwent routine pathological examination. Results: Varying degrees of nervous system positive signs were observed in all the injured rabbits. Within 6 hours, the mortality rate was 1/10 in the minor injury group and 6/10 in the severe injury group. Morphological changes con-sisted of different levels of scalp hematoma, skull fracture, epidural hematoma, subdural hematoma, subarachnoid hemo-rrhage and brain injury. At the moment of hitting, the ICP was greater in severe injury group than in mild injury group; and within the same group, the impact side showed positive pressure while the opposite side showed negative pressure. Conclusions: Under the rigidly-controlled experimen-tal condition, this animal model has a good reproducibility and stable results. Meanwhile, it is able to simulate the mor-phology of iron strike-induced injury, thus can be used to study the mechanism of blunt head injury in forensic medicine. Key words: Brain injuries; Forensic medicine; Wounds, nonpenetrating; Models, animal; Rabbit