Anderson Kevin J, Scheff Stephen W, Miller Kelly M, Roberts Kelly N, Gilmer Lesley K, Yang Cui, Shaw Gerry
Department of Physiological Sciences, McKnight Brain Institute, University of Florida, Gainesville, Florida 32610, USA.
J Neurotrauma. 2008 Sep;25(9):1079-85. doi: 10.1089/neu.2007.0488.
The detection of neuron-specific proteins in blood might allow quantification of the degree of neuropathology in experimental and clinical contexts. We have been studying a novel blood biomarker of axonal injury, the heavily phosphorylated axonal form of the high molecular weight neurofilament subunit NF-H (pNF-H). We hypothesized that this protein would be released from damaged and degenerating neurons following experimental traumatic brain injury (TBI) in amounts large enough to allow its detection in blood and that the levels detected would reflect the degree of injury severity. An enzyme-linked immunosorbent assay (ELISA) capture assay capable of detecting nanogram amounts of pNF-H was used to test blood of rats subjected to experimental TBI using a controlled cortical impact (CCI) device. Animals were subjected to a mild (1.0 mm), moderate (1.5 mm), or severe (2.0 mm) cortical contusion, and blood samples were taken at defined times post-injury. The assay detected the presence of pNF-H as early as 6 h post-injury; levels peaked at 24-48 h, and then slowly decreased to baseline over several days post-injury. No signal above baseline was detectable in control animals. Analysis of variance (ANOVA) showed a significant effect of lesion severity, and post hoc analysis revealed that animals given a moderate and severe contusion showed higher levels of blood pNF-H than controls. In addition, the peak levels of pNF-H detected at both 24 and 48 h post-injury correlated with the degree of injury as determined by volumetric analysis of spared cortical tissue. Relative amounts of pNF-H were also determined in different areas of the central nervous system (CNS) and were found to be highest in regions containing large-diameter axons, including spinal cord and brainstem, and lowest in the cerebral cortex and hippocampus. These findings suggest that the measurement of blood levels of pNF-H is a convenient method for assessing neuropathology following TBI.
检测血液中的神经元特异性蛋白质可能有助于在实验和临床环境中量化神经病理学程度。我们一直在研究一种新型的轴突损伤血液生物标志物，即高分子量神经丝亚基NF-H的高度磷酸化轴突形式（pNF-H）。我们假设，在实验性创伤性脑损伤（TBI）后，这种蛋白质会从受损和退化的神经元中释放出来，其释放量足以使其在血液中被检测到，并且检测到的水平将反映损伤的严重程度。使用一种能够检测纳克量pNF-H的酶联免疫吸附测定（ELISA）捕获测定法，对使用控制皮质撞击（CCI）装置进行实验性TBI的大鼠血液进行检测。动物接受轻度（1.0毫米）、中度（1.5毫米）或重度（2.0毫米）皮质挫伤，并在损伤后的特定时间采集血样。该测定法最早在损伤后6小时检测到pNF-H的存在；水平在24 - 48小时达到峰值，然后在损伤后的几天内缓慢降至基线。在对照动物中未检测到高于基线的信号。方差分析（ANOVA）显示损伤严重程度有显著影响，事后分析表明，接受中度和重度挫伤的动物血液中pNF-H水平高于对照组。此外，在损伤后24小时和48小时检测到的pNF-H峰值水平与通过对保留的皮质组织进行体积分析确定的损伤程度相关。还测定了中枢神经系统（CNS）不同区域pNF-H的相对含量，发现其在包含大直径轴突的区域最高，包括脊髓和脑干，而在大脑皮质和海马体中最低。这些发现表明，测量血液中pNF-H水平是评估TBI后神经病理学的一种便捷方法。
