脑震荡对大鼠认知行为及前额叶皮质多巴胺能神经纤维的影响

目的:探讨脑震荡(BC)大鼠认知障碍的特征及其与前额叶皮质(PFC)多巴胺能神经纤维变化的关系。方法:用金属单摆打击装置复制大鼠单纯性BC模型,伤后分1~24 d多个损伤组;用Morris水迷宫评价大鼠的学习记忆功能;用免疫组织化学技术研究BC后PFC多巴胺能神经纤维的变化。结果:BC伤后1~3 d大鼠隐匿平台逃避潜伏期显著延长,BC后除1 d外,其余各组PFC多巴胺能神经纤维的密度和免疫反应显著高于对照组。结论:BC后大鼠出现近期空间学习记忆功能障碍,多巴胺能神经纤维TH表达增高并持续一段时间。TH早期增高可能是神经递质紊乱,随后持续增高可能是一种代偿反应。

Influence of cerebral concussion on cognitive behavior and dopaminergic nerve fiber in prefrontal cortex of rats

Objective: To study the cognitive disorders in brain concussion(BC) rats and to explore the relationship between cognitive disorders and the dopaminergic nerve fibers in prefrontal cortex(PFC).Methods:Animal model of concussive brain injury was duplicated in rats with a metallic pendulum-striker concussive device.BC animals were divided into 6 groups of 1-24 d.Learning and memory ability of animal were evaluated by Morris water maze method.The changes of dopaminergic nerve fibers in prefrontal cortex were studied by immunohistochemistry method.Results: The escape latencies in treated group were statistically longer than that in the control group on 1 d-3 d post-concussion.The density and intensity of the TH-immunoreaction(TH-IR) in PFC increased statistically in each group except for 1d after BC.Conclusion:The spatial learning and memory deficits of the rats are found in early period of post-BC.The expression of TH-IR in dopaminergic nerve fibers in PFC increased following BC.The increase in TH in earlier period may be caused by neuronal transient overexcitation,and the increase in TH remains for a period of time may be a compensatory response.