摘要
目的:研制一种联合直线加速及旋转加速损伤的弥漫性轴索损伤(DAI)的致伤装置,通过设置不同的机械参数复制出不同损伤级别的DAI。方法:36只小鼠随机分为对照组(6只)及损伤组(30只),其中损伤组分为轻度、中度、重度三亚组,每亚组各10只。采用自行设计的重物打击联合旋转加减速致伤的装置,三亚组分别使用不同的致伤参数(即打击棒质量、高度及旋转角度分别为:轻度亚组50 g×60 cm/22.5°、中度亚组100 g×60 cm/45°、重度亚组150 g×60 cm/90°),并于伤后24 h处死,行淀粉样前体蛋白(APP)及神经微丝(NF-200)免疫组化染色,以观测神经轴索的损伤特征,同时观察各组小鼠伤后行为学改变。结果:损伤组的神经反射恢复时间均比对照组延长,且重度亚组耗时最长,中度亚组次之,轻度亚组最短。伤后24 h各组小鼠死亡率依次为:对照组0%,轻度亚组0%,中度亚组10%,重度亚组30%。APP和NF-200免疫组化染色呈不同程度阳性结果;重度亚组阳性结果最明显,有大量的神经组织肿胀和轴索损伤阳性染色特征等;轻度亚组仅有少量点状脑出血,各轴索损伤阳性结果较少出现;中度亚组可发现上述DAI形态学特征但没有重度亚组明显。结论:本实验成功建立一种联合直线加速及旋转加速损伤的DAI机械装置,通过设置不同的机械参数可复制出不同损伤级别的DAI小鼠;该装置操作简单、重复性强、稳定性好。
Objective: A new experimental device for diffuse axonal injury(DAI) was designed and manufactured in which the basic mechanism was the combination of angular and linear acceleration. The device was able to replicate graded DAI of different severity by regulating the mechanical parameters. Methods:Thirty-six mice were randomly divided into the control group(n=6) and injury group(n=30); the injury group was further divided into the mild, moderate, and severe subgroups with 10 mice in each. The mice in the three injury subgroups were subjected to coronal rotation after weight-drop impact injury using a newly manufactured device; the mechanical parameters(impact baton's mass and rotation angle) of the mild, moderate, and severe DAI subgroups were 50 g × 60 cm/22.5°, 100 g × 60 cm/45°, and 150 g × 60 cm/90°, respectively. The mice were sacrificed 24 hours post-injury, and immunohistochemical visualization of amyloid precursor protein(APP) and neurofilament(NF-200) was performed to assess characteristics of axonal damage. Behavioral changes of the injured mice were also evaluated. Results: All mice in the injury group showed longer latency for reflex recovery than mice in the control group, with the severe, moderate, and mild DAI subgroups respectively showing the longest, second longest, and shortest latency. The post-injury mortality rates of mice in the control group and the mild, moderate, and severe DAI subgroups were 0%, 0%, 10%, and 30%, respectively.Immunohistochemical visualization of APP and NF-200 showed varying degrees of positive staining; the severe DAI subgroup showed the strongest positive signal characterized by large amounts of nerve tissue swelling and axonal damage. The moderate DAI subgroup also displayed the above morphological characteristics but not with the same intensity as the severe DAI subgroup. Immunohistochemical staining of APP and NF-200 in the mild DAI subgroup showed only minimal, localized intracranial bleeding with relatively few positive signals.Conclusion: A novel device that combines linear and rotational acceleration injury mechanisms for establishing the DAI experimental model has been successfully created. Different degrees of injury can be induced by varying mechanical parameters to establish graded DAI in mice. This device demonstrates good usability, repeatability,and reliability.
引文
[1]Johnson VE,Stewart W,Smith DH.Axonal Pathology in Traumatic Brain Injury[J].Exp Neurol,2013,246:35-43.
[2]Rabinowitz AR,Smith DH.Traumatic Brain Injury and Rationale for a Neuropsychological Diagnosis of Diffuse Axonal Injury[J].Genes Environment&Alzheimers Disease,2016:267-293.
[3]Dai JX,Ma YB,Le NY,et al.Large Animal Models of Traumatic Brain Injury[J].Int J Neurosci,2018,128:243-254.
[4]Lu H,Ma K,Jin L,et al.17β-estradiol rescues damages following traumatic brain injury from molecule to behavior in mice[J].J Cell Physiol,2017,233:1712-1722.
[5]王清涛,史立信,臧颖卓,等.急性酒精中毒合并弥漫性轴索损伤大鼠脑干AQP4表达和磁共振弥散张量成像研究[J].神经损伤与功能重建,2017,12:388-391.
[6]Wang HC,Duan ZX,Wu FF,et al.A new rat model for diffuse axonal injury using a combination of linear acceleration and angular acceleration[J].J Neurotrauma,2010,27:707-719.
[7]Dewitt DS,Perez-Polo R,Hulsebosch CE,et al.Challenges in the development of rodent models of mild traumatic brain injury[J].JNeurotrauma,2013,30:688-701.
[8]Pierce JE,Trojanowski JQ,Graham DI,et al.Immunohistochemical characterization of alterations in the distribution of amyloid precursor proteins and beta-amyloid peptide after experimental brain injury in the rat[J].J Neurosci,1996,16:1083-1090.
[9]Li J,Li XY,Feng DF,et al.Biomarkers associated with diffuse traumatic axonal injury:exploring pathogenesis,early diagnosis,and prognosis[J].J Trauma,2010,69:1610-1618.
[10]Lee JC,Park JH,Ahn JH,et al.Effects of chronic scopolamine treatment on cognitive impairment and neurofilament expression in the mouse hippocampus[J].Mol Med Rep,2018,17:1625-1632.