Huang Xian-Jian, Glushakova Olena, Mondello Stefania, Van Ken, Hayes Ronald L, Lyeth Bruce G
1 Department of Neurosurgery, Shenzhen University 1st Affiliated Hospital , Shenzhen, China .
2 Department of Neurological Surgery, University of California at Davis , Davis, California.
J Neurotrauma. 2015 Aug 15;32(16):1179-89. doi: 10.1089/neu.2015.3873. Epub 2015 May 14.
A number of potential traumatic brain injury (TBI) biomarkers have been proposed and evaluated in the laboratory and clinic. This study investigated the temporal profile of circulating biomarkers of astrocytic and neuronal injury over the first 24 h and relevant histopathological changes after experimental moderate TBI. Twenty male rats were randomly assigned to either moderate parasagittal fluid percussion or sham injury. Blood serum samples were collected 2 d prior to TBI (baseline) and at 3, 6, and 24 h after TBI. A single cerebrospinal fluid (CSF) sample was collected from the cisterna magna 24 h after TBI, followed by euthanasia and brain harvesting for histology. Serum and CSF samples were analyzed for neuronal (ubiquitin carboxy-terminal hydrolase L1 [UCH-L1]) and astroglial (glial fibrillary acidic protein [GFAP]) protein levels using enzyme-linked immunosorbent assay. Brain histology included GFAP immunostaining and Fluoro-Jade histofluorescence. Serum and CSF levels of GFAP were near zero in sham animals. Serum GFAP levels were significantly elevated at 3 and 6 h post-TBI, compared with baseline and time-matched sham values, while UCH-L1 was significantly elevated only at 3 h post-TBI. Both CSF GFAP and UCH-L1 at 24 h post-TBI were significantly elevated, compared with sham. GFAP immunohistochemistry and FJ histofluorescence of degenerating neurons were performed in the same animals after 24 h survival. Histology revealed characteristic acute neuronal degeneration in the ipsilateral hippocampus and parietal cortex and reduction in GFAP immunostaining in areas of neuronal cell loss. The data provide evidence of a causal relationship between TBI-induced acute brain pathology and circulating neuronal and glial markers, further demonstrating their role as candidate markers for TBI. Studies of relative changes in biomarker levels in CSF and serum suggest that different mechanisms may underlie the transport and/or clearance of UCH-L1 and GFAP in these two compartments.
在实验室和临床中，人们已经提出并评估了许多潜在的创伤性脑损伤（TBI）生物标志物。本研究调查了实验性中度TBI后最初24小时内星形胶质细胞和神经元损伤循环生物标志物的时间变化情况以及相关的组织病理学变化。将20只雄性大鼠随机分为中度矢状旁流体冲击伤组或假伤组。在TBI前2天（基线）以及TBI后3、6和24小时采集血清样本。在TBI后24小时从枕大池采集一份脑脊液（CSF）样本，随后实施安乐死并取脑进行组织学检查。使用酶联免疫吸附测定法分析血清和CSF样本中神经元（泛素羧基末端水解酶L1 [UCH-L1]）和星形胶质细胞（胶质纤维酸性蛋白 [GFAP]）的蛋白水平。脑组织学检查包括GFAP免疫染色和荧光玉组织荧光检查。假伤动物的血清和CSF中GFAP水平接近零。与基线和时间匹配的假伤值相比，TBI后3和6小时血清GFAP水平显著升高，而UCH-L1仅在TBI后3小时显著升高。与假伤组相比，TBI后24小时CSF中的GFAP和UCH-L1均显著升高。在存活24小时后的同一批动物中进行了GFAP免疫组织化学和变性神经元的FJ组织荧光检查。组织学检查显示同侧海马和顶叶皮质有特征性的急性神经元变性，并且在神经元细胞丢失区域GFAP免疫染色减少。这些数据提供了TBI诱导的急性脑病理与循环神经元和胶质标志物之间因果关系的证据，进一步证明了它们作为TBI候选标志物的作用。对CSF和血清中生物标志物水平相对变化的研究表明，这两个区室中UCH-L1和GFAP的转运和/或清除可能存在不同机制。
