脑缺血后血清NSE和S?100蛋白含量变化与磁共振弥散成像关系

【摘要】  目的 对比分析兔脑缺血后磁共振弥散成像（DWI）的信号、大小变化与脑组织神经元特异性烯醇化酶（NSE）和S?100蛋白血清含量变化的关系，探讨血清NSE和S?100蛋白诊断脑梗死及监测脑梗死动态变化的可行性。方法将制作成功的大脑中动脉栓塞(MCAO)模型兔30只分为6组，即缺血1、3、6、12、24、48 h组，每组5只。另取5只动物行假手术作为对照组。每组分别于各自时间点进行MRI弥散成像，分别测量弥散系数（ADC）值、相对ADC（rADC）值和异常信号区的相对面积。免疫组化法检测脑缺血不同时间脑组织NSE和S?100蛋白的表达，ELISA法检测血清NSE和S?100蛋白的含量。结果 兔脑缺血6 h后血清中NSE和S?100蛋白含量显著升高，至缺血24 h达到高峰，48 h后下降；DWI缺血1 h显示明显的高信号并伴有ADC值的下降，在不同的缺血时间点，各组平均ADC值呈先下降后上升的趋势，其中缺血6 h时ADC值最低，以后逐渐升高，48 h恢复至略高于1 h时水平。结论 NSE与S?100蛋白血清学检测可以作为诊断脑梗死动态变化的一项指标，但不是早期诊断脑梗死的有效方法。 
【关键词】  磁共振弥散成像；脑缺血；神经元特异性烯醇化酶；S?100蛋白质
［ABSTRACT］ Objective A contrast analysis was done on the association between diffusion weighted imaging (DWI) signal and its changes as well as neuron?specific enolase (NSE) and S?100 protein, and explore the feasibility of the diagnosis of cerebral infarction and monitoring its dynamic changes by detecting serum NSE and S?100 protein. Methods Thirty successfully?completed middle?cerebral?artery?occlusion (MCAO) rabbit models were equally divided into six groups; 1 h?, 3 h?, 6 h?, 12 h?, 24 h? and 48 h?groups. Another five rabbits served as the control. An MRI was done for all groups at their own time point, the apparent dispersion coefficient (ADC) and the rADC value and the relative areas of abnormal signal regions were measured. The expressions of NSE and S?100 protein in brain tissue were determined with immunochemical assay, serum NSE and S?100 protein were measured with enzyme?linked immunosorbent assay (ELISA). Results The serum NSE and S?100 protein dramatically increased starting six hours after the occurrence of brain ischemia, reaching the peak at 24 hours, and then declined. DWI showed marked high signal at one hour after ischemia following decrease of ADC value. At different ischemic time points, the average ADC value in various groups showed a tendency of rising first and then breakdown, during which, the lowest ADC appeared at six hours after ischemia and gradually increased afterward, reached the level of a little higher than at one?hour?time?point level at 48 hours.  ConclusionA detection of serum NSE and S?100 protein can be used as an index of dynamic changes of cerebral infarction, but it is not effective for an early diagnosis of this disease.
    ［KEY WORDS］ Diffusion weighted imaging; Brain ischemia; Neuron?specific enolase; S?100 protein
    缺血性脑损伤是多种酶和蛋白质共同参与的过程，其中神经元特异性烯醇化酶（NSE）和S?100蛋白被认为是诊断缺血性脑损伤敏感的神经生化指标[1,2]。NSE是一种特异地存在于神经细胞和神经内分泌细胞中的蛋白质，神经胶质细胞和其他脑神经组织中不含NSE，故NSE是神经元损伤的标志酶[3]。S?100 蛋白是一类酸性可溶性蛋白质，主要位于中枢神经系统的星形胶质细胞、少突胶质细胞以及周围神经的雪旺细胞内，是神经胶质细胞的标记蛋白。作为神经系统损伤的特异性标志，NSE和S?100蛋白在脑脊液或血液中的水平可反映神经系统损伤的程度和范围。本研究应用酶联免疫吸附法（ELISA）测定兔脑缺血不同时间血清中NSE和S?100蛋白的含量，同时分析缺血脑组织磁共振弥散成像（MR?DWI）病变面积、弥散系数（ADC）和相对弥散系数（rADC）的变化，通过对比分析，探讨血清NSE和S?100蛋白诊断脑梗死及监测脑梗死动态变化的可行性。现将结果报告如下。