Department of Biomedical Engineering, Wayne State University, Detroit, Michigan 48201, USA.
J Neurotrauma. 2011 Sep;28(9):1767-82. doi: 10.1089/neu.2010.1687. Epub 2011 Sep 6.
A modified Marmarou impact acceleration model was developed to study the mechanical responses induced by this model and their correlation to traumatic axonal injury (TAI). Traumatic brain injury (TBI) was induced in 31 anesthetized male Sprague-Dawley rats (392±13 g) by a custom-made 450-g impactor from heights of 1.25 m or 2.25 m. An accelerometer and angular rate sensor measured the linear and angular responses of the head, while the impact event was captured by a high-speed video camera. TAI distribution along the rostro-caudal direction, as well as across the left and right hemispheres, was determined using β-amyloid precursor protein (β-APP) immunocytochemistry, and detailed TAI injury maps were constructed for the entire corpus callosum. Peak linear acceleration 1.25 m and 2.25 m impacts were 666±165 g and 907±501 g, respectively. Peak angular velocities were 95±24 rad/sec and 124±48 rad/sec, respectively. Compared to the 2.25-m group, the observed TAI counts in the 1.25-m impact group were significantly lower. Average linear acceleration, peak angular velocity, average angular acceleration, and surface righting time were also significantly different between the two groups. A positive correlation was observed between normalized total TAI counts and average linear acceleration (R(2)=0.612, p<0.05), and time to surface right (R(2)=0.545, p<0.05). Our study suggested that a 2.25-m drop in the Marmarou model may not always result in a severe injury, and TAI level is related to the linear and angular acceleration response of the rat head during impact, not necessarily the drop height.
改良 Marmarou 冲击加速度模型用于研究该模型诱导的力学响应及其与创伤性轴索损伤（TAI）的相关性。通过定制的 450 克冲击器，在 1.25 米或 2.25 米高度，对 31 只麻醉雄性 Sprague-Dawley 大鼠（392±13g）造成创伤性脑损伤（TBI）。加速度计和角速度传感器测量头部的线性和角运动响应，同时高速摄像机捕获冲击事件。使用β-淀粉样前体蛋白（β-APP）免疫细胞化学确定沿头尾方向以及左右半球的 TAI 分布，并构建整个胼胝体的详细 TAI 损伤图谱。1.25m 和 2.25m 冲击的峰值线性加速度分别为 666±165g 和 907±501g，峰值角速度分别为 95±24rad/sec 和 124±48rad/sec。与 2.25m 组相比，1.25m 冲击组观察到的 TAI 计数明显较低。两组间的平均线性加速度、峰值角速度、平均角速度和表面翻转时间也有显著差异。归一化总 TAI 计数与平均线性加速度呈正相关（R²=0.612，p<0.05），与表面翻转时间呈正相关（R²=0.545，p<0.05）。本研究表明，Marmarou 模型中 2.25m 的下降不一定会导致严重损伤，并且 TAI 水平与冲击过程中大鼠头部的线性和角加速度响应有关，而不一定与下降高度有关。
