Mild concussive events without loss of consciousness are typically left untreated and can result in neurological abnormalities at later stages of life. No systematic studies have been carried out to determine the effect of concussion or repeated mild concussive episodes on brain vulnerability towards blast exposure. We have evaluated the effect of repeated mild concussive events on the vulnerability of brain to blast exposure using neurobehavioral functional assessments. Rats were subjected to either repeated mild concussive impacts (two impacts one week apart using a modified Marmarou weight drop model), a single blast exposure (19 psi using an advanced blast simulator), or a single blast exposure one day after the second mild concussive impact. Neurobehavioral changes were monitored using rotating pole test, open field exploration test, and novel object recognition test. Rotating pole test results indicated that vestibulomotor function was unaffected by blast or repeated mild concussive impacts, but significant impairment was observed in the blast exposed animals who had prior repeated mild concussive impacts. Novel object recognition test revealed short-term memory loss at 1-month post-blast only in rats subjected to both repeated mild concussive impacts and blast. Horizontal activity count, ambulatory activity count, center time and margin time legacies in the open field exploratory activity test indicated that only those rats exposed to both repeated mild concussive impacts and blast develop anxiety-like behaviors at both acute and sub-acute time points. The results indicate that a history of repeated mild concussive episodes heightens brain vulnerability to blast exposure.

中文翻译：

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反复发生的轻度脑震荡事件会增加大脑在爆炸暴露下的脆弱性。

没有意识丧失的轻度脑震荡事件通常不予治疗，可能会导致生命后期的神经系统异常。尚未进行系统研究来确定脑震荡或反复轻度脑震荡事件对大脑对爆炸暴露的脆弱性的影响。我们使用神经行为功能评估评估了重复的轻度震荡事件对大脑对爆炸暴露的脆弱性的影响。大鼠遭受重复的轻度震荡冲击（使用改良的 Marmarou 体重下降模型，间隔一周两次冲击）、单次爆炸暴露（使用先进的爆炸模拟器 19 psi），或在第二次轻度震荡一天后遭受单次爆炸暴露影响。使用旋转杆测试、旷场探索测试和新物体识别测试来监测神经行为变化。旋转杆测试结果表明，前庭运动功能未受到爆炸或重复轻度震荡冲击的影响，但在先前遭受过重复轻度震荡冲击的爆炸暴露动物中观察到显着损害。新颖的物体识别测试显示，仅遭受重复轻度震荡冲击和爆炸的老鼠在爆炸后 1 个月时出现短期记忆丧失。旷场探索活动测试中的水平活动计数、动态活动计数、中心时间和边缘时间遗产表明，只有那些同时暴露于重复轻度震荡和爆炸的大鼠才会在急性和亚急性时间点出现焦虑样行为。结果表明，反复发生轻度脑震荡的病史会增加大脑对爆炸暴露的脆弱性。