兔脑缺血再灌注神经元特异性烯醇化酶和S-100蛋白表达与表观弥散系数值变化的对比

Comparison study on the expressions of neuron-specific enolase and S-100 proteins and the apparent dispersion coefficient value in MRI-DWI following cerebral ischemia and reperfusion in rabbits

目的分析兔脑缺血及再灌注后脑组织神经元特异性烯醇化酶（NSE）和S-100蛋白的表达与磁共振弥散成像（MRI-DWI）表观弥散系数（ADC值）的变化,探讨在诊断脑梗死及监测脑梗死动态变化方面的应用价值。方法兔大脑中动脉缺血及再灌注（MCAO/R）模型58只,随机分为永久缺血组和再灌注组。其中永久性缺血组分为缺血1、3、6、12、24、48 h组,每组5只;再灌注组缺血1 h拔线再通后分为再灌注0 h（5只）、2 h（5只）、5 h（5只）、11 h（4只）、23 h（5只）和47 h（4只）组。另取10只动物行假手术作为对照组。分别于兔脑缺血和再灌注不同时间点进行MRI-DWI,测量ADC值;免疫组化方法测定不同时间点脑组织中NSE和S-100蛋白的表达。结果脑缺血1 h脑组织NSE和S-100蛋白的表达明显增强。缺血12 h和再灌注11 h达高峰,此后逐渐下降。再灌注组表达程度低于缺血组,再灌注后23~47 h表达再次上调。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。缺血组缺血1 h均可显示DWI上明显高信号并伴有ADC值的下降,至缺血6 h时ADC值最低。再灌注5 h ADC降到最低。再灌注23~47 h,ADC值出现再次下降,与脑组织NSE和S-100蛋白表达再次上调相对应。结论脑组织NSE和S-100蛋白的表达对缺血性脑损害具有较高的特异性和敏感性。ADC值的变化对缺血性脑梗死具有高敏感性和特异性,与脑组织NSE和S-100蛋白的表达变化基本一致。

Objective To discuss the clinical application value of the expressions of neuron-specific enolase（NSE） and S-100 proteins and the apparent dispersion coefficient（ADC）value in magnetic resonance diffusion weighted imaging（MRIDWI）in diagnosing cerebral infarction and monitoring the development of cerebral infarction by analyzing the changes of the expressions of NSE and S-100 proteins and the ADC value in MRI-DWI after middle cerebral artery occlusion and reperfusion（MCAO/R） in rabbits.Methods Fifty-eight successful MCAO/R rabbit models were divided into permanent ischemia group（A group,n=30） which were subdivided into ischemic 1,3,6,12,24,48 h groups（n=5 each group） and reperfusion group after 1 h cerebral ischemia（B group,n=28） which were subdivided into 2 h（n=5）,5 h（n=5）,11 h（n=4）,23 h（n=5）,47 h（n=4） groups. Another 10 rabbits were regarded as ischemic control group.All rabbit brains were cut out to make histologic section immediate after each time point MRI examination,then measured the ADC value.The expressions of NSE and S-100 proteins in the brain tissue were determined with immunochemical assay.Results The expressions of NSE and S-100 proteins increased markedly following permanent ischemic 1 h,and reached a peak at permanent ischemic 12 h and ischemic reperfusion 11 h.After that,the expressions of NSE and S-100 proteins were gradually descent and then increased.The expressions of NSE and S-100 proteins in reperfusion groups were weaker than that in permanent ischemic groups,and increased again at reperfusion 23～47 h.The average ADC value decreased at first and then increased gradually at different time points.There were significant signals with the decrease of ADC value at ischemic 1 h point in permanent ischemia groups,and the low peak was at permanent ischemic 6 h and reperfusion 5 h,and decreased again at reperfusion 23～47 h,which was corresponded with the expression of NSE and S-100 proteins.Conclusions The expressions of NSE and S-100 proteins in the brain tissue are impressionable and specific in discovering cerebral infarction.MRI-DWI and the ADC value are highly impressionable and specific in discovering cerebral infarction and reperfusion injury,and even outweigh the expressions of NSE and S-100 proteins in the brain tissue.