大鼠可控性皮质撞击不同程度损伤模型的构建

Establishment and different severity traumatic brain injury model induced by controlled cortical impact in rats

目的:采用自主研发的电子可控性皮质撞击仪(eCCI)对幼年期大鼠构成不同程度的颅脑创伤(TBI),探索出不同程度颅脑损伤的对应参数设置及外伤后皮层脑电(ECo G)痫样改变的初步特征。方法:35只SD雄性大鼠随机分为4组,其中轻、中、重损伤组共3组,假手术组1组。分别采用不同打击深度打击大鼠顶叶皮质区域;假手术组操作同损伤组,但不进行皮质打击。所有实验动物分别于致伤前1 d,致伤后1、3、5、7 d行改良后啮齿类动物神经功能缺陷评分法(NSS-R)观察大鼠致伤后行为学改变。伤后2 d取脑组织行HE染色、尼氏染色、免疫组化染色观察TBI后脑组织的病理学改变;采用透射电镜观察神经细胞超微结构的改变,致伤后30 d植入皮层记录电极采集并分析大鼠皮层的脑电情况。结果:大鼠损伤程度与打击深度相关,打击深度1 mm模拟轻度颅脑创伤,打击深度3 mm模拟中度颅脑创伤,打击深度5 mm模拟重度颅脑创伤,与假手术组相比,损伤组TBI后1 d神经功能缺陷评分及损伤组间差异比较有显著性(P <0. 05),脑皮质结构遭到不同程度破坏,中度损伤组术后30 d,可观察到皮层痫样放电。结论:应用自主研发的eCCI撞击仪成功建立可控性大鼠TBI模型。

Objective: To establish the controlled cortical impact ( CCI)-induced traumatic brain injury ( TBI) in immature rats with different severity in degree and explore the corresponding setting parameters. The preliminary characteristics of electrocorticogram ( ECoG) in post-traumatic epilepsy. Methods: A total of 35 male Sprague Dawley immature rats were randomly divided into four groups, which were named 3 impact groups ( n = 9) and control group ( n = 8 ), The parietal cortex of rats were hit with different depth, control-operated group was subjected to craniectomy without impacting, then suturing. Neurologic function change were observed by the revised neurobehavioral severity scale ( NSSR) on the 1st before operation and the 1st, 3rd, 5th, 7th day after operation. On the 2nd after operation, the brain tissue was stained with HE, Nissl and immunohistochemical methods to observe the degree of cerebral cortical defect and the morphological changes were observed, ultrastructural changes of nerve cells observed by transmission electron microscope. Then the EEG was collected by 30 days after TBI. Results: The degree of injury was obswrved to be related to the depth of impact, 1 mm group simulated mild craniocerebral traum, 3 mm group simulated moderate craniocerebral traum, 5 mm group simulated severe craniocerebral traum. Compared with the control operation group, the NSS-R and the difference between the injury groups were significant on the first day after TBI (P <0. 05), the structure of cerebral cortex was destroyed with varying degrees. In addition, the abnormal EEG in cortex of rats could be observed when the impact depth was 3 mm by 30 days after TBI. Conclusion: The TBI model of rats was successfully established by using self-research eCCI impator.