Intracerebral expression pattern of various transported protein through axons and proinflammatory cytokines after fatal traumatic brain injury

本研究旨在建立以下三种方法：(1)弥漫性创伤性轴索损伤(TAI)的新的法医诊断标志物；(2)创伤性轴索损伤与缺氧性轴索损伤的鉴别诊断；(3)损伤后时间间隔的估计。为此，我们用免疫组织化学方法检测了脑内通过轴突转运的蛋白如β-淀粉样前体蛋白(APP)、神经元特异性烯醇化酶(NSE)的表达，以及促炎细胞因子如IL-8、肿瘤坏死因子-α(α)的表达。用免疫组织化学方法对颅脑损伤患者的胼胝体切片进行了上述标记。在APP和NSE免疫组织化学染色切片上，在几例颅脑损伤患者中发现了两种免疫反应模式。第一种模式显示标记的轴突与白质束一起定向；第二种模式显示轴突不规则散布。我们的结果提示，第一种模式可能代表创伤性轴索损伤，第二种模式可能代表继发性缺氧性轴索损伤。此外，NSE是比APP更敏感的检测TAI的方法，因为NSE免疫组织化学染色可以检测存活超过2小时(APP；超过9小时)的颅脑损伤患者的轴突损伤。此外，IL-8和肿瘤坏死因子-α免疫组织化学染色可检测存活3天以上和4天以上的颅脑损伤患者的轴索损伤。本研究结果提示，IL-8、肿瘤坏死因子-α等促炎细胞因子的免疫组织化学染色可作为判断创伤性轴索损伤后时间间隔的新指标。

This research aimed to establish the following three methods ; (1) new forensic diagnostic markers for diffuse traumatic axonal injury (TAI), (2) differential diagnosis between traumatic axonal injury and hypoxic one, (3) estimation for time interval after injury. For this purpose, we immunohistochemically examined intracerebral expressions of transported proteins through axons such as β-amyloid precursor protein (APP), Neuron-specific enolase (NSE), and expressions of proinflammatory cytokines such as Interleukin-8 (IL-8), Tumor necrosis factor-α (TNF-α). Sections of the corpus callosum from cases of head injury were immunostained for those markers. On both APP and NSE immunostained sections, two patterns of immunoreactivity were identified in several cases of head injury. The first pattern showed that labeled axons were oriented along with white matter bundles ; the second demonstrated that the axons were scattered irregularly. Our results suggested that the first and second pattern may represent traumatic axonal injury, and secondary hypoxic axonal injury, respectively. Moreover, NSE was more sensitive procedure for detecting TAI than APP, because NSE immunostaining could detect axonal injuries in cases of head injury that survived more than 2 hours (APP ; more than 9 hours). Furthermore, IL-8 and TNF-α immunostaining could detect axonal injuries in cases of head injury that survived more than 3 days and 4 days, respectively. Our results suggested that immunostaining of proinflammatory cytokines such as IL-8 and TNF-α in the corpus callosum could be a new useful marker for estimating time interval after traumatic axonal injury.