摘要目的 根据弥漫性轴索损伤(DAI)临床实际力学发生机制,在联合损伤模型基础上探讨直线加速和旋转加速的联合损伤效应. 方法 116只SD大鼠采用随机数字表法分为正常对照组(8只)、单纯损伤组(72只){包括单纯打击直线加速损伤组(36只,大鼠接受450 g钢砝码于0.9m高处坠落打击后直线加速1 cm)和单纯旋转加速损伤组[36只,大鼠发生最大角加速度为(133±15) krad/s2的90°旋转]}及联合损伤组(36只,大鼠接受上述打击直线和旋转加速的复合损伤过程).观察大鼠伤后存活情况、角膜反射消失时间及组织病理学改变. 结果 (1)各损伤组大鼠均出现角膜反射消失时间的延长及肢体活动减少等行为学抑制表现,但联合损伤组较单纯损伤组明显.大鼠死亡仅限于联合损伤组,死亡率达20.8％.(2)各损伤组大鼠大体及HE染色均见蛛网膜下腔或脑室出血及脑组织结构疏松水肿等病理学改变,但脑白质撕裂性出血及HE染色轴索损伤征象仅见于联合损伤组;β-聚磷酸铵免疫组化染色及电镜仅观察到联合损伤组大鼠存在轴索损伤. 结论 单一直线加速或旋转加速在低水平力学参数下难以产生DAI,但两者联合可产生协同和非线性效应而使两种力学在较低水平情况下复制出中、重型DAI.

abstractsObjective To investigate the combined injury effect of impact linear acceleration and angular acceleration by exploring the combined injury mechanism of diffuse axonal injury (DAI).Methods According to the mechanism ofDAI,a new experimental facility was designed.This model let the rats instantly rotate 90 degree after being experienced impact injury and linear acceleration.Group 1 animals,a 450 g weight was dropped from a height of 0.9 m with no subsequent rotation (n=36); group 2 animals underwent purely angular acceleration with no preceding impact-acceleration injury (n=36); group 3 animals were subjected to the combined linear and angular accelerations (n=36); group 4 animals served as the controls (n=8).Pathologic and behavioral examinations were conducted to verify characteristics of DAI.Results (1) Group 3 animals took significantly longer time to regain corneal reflex (12.1 ±3.4 min) and had decreased limb exercise as compared with other groups (P＜0.05).Besides,mortality was only observed in Group 3,reaching 20.8％.(2) Macroscopic damage was observed in all brain-injured animals.However,axonal damage and hemorrhagic tissue tears were only noted in Group 3.Both β-APP immunohistochemistry and electron microscopy indicated axonal injury only in Group 3.Conclusions The combination of impact linear and angular accelerations can cause non-linear and synergistic effects to produce severe DAI with mild levels of both forms of acceleration.