大鼠脑缺血再灌注损伤后不同时间脑损伤区DWI信号强度与表观扩散系数变化分析
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摘要
目的分析大鼠脑缺血再灌注损伤(CIRI)后不同时间脑损伤区弥散加权成像(DWI)信号强度与表观扩散系数的变化。方法取64只健康成年雄性SD大鼠,按照随机分配原则,分为假手术组(血管分离后即刻缝合)和实验组[通过改良线栓法建立大鼠脑缺血再灌注(CIR)模型];根据实验组CIR时间的不同分为CIR-1 h组、CIR-3 h组、CIR-6 h组、CIR-12 h组、CIR-24 h组、CIR-3 d组、CIR-7 d组,每组各8只。采用Zea Longa评分对各组大鼠神经功能损伤程度进行评估。采用3. 0 T磁共振扫描仪对各组大鼠行冠状位DWI扫描,对基底核层面梗死灶DWI的表观扩散系数和信号强度进行测量,并计算相对DWI信号强度和相对表观扩散系数。采用TTC染色法对各组大鼠脑梗死体积进行评估,并用HE染色法观察大鼠组织形态学变化情况。结果麻醉苏醒后,假手术组大鼠无神经功能损伤; CIR-1 h组、CIR-3 h组、CIR-6 h组、CIR-12 h组、CIR-24 h组大鼠随着时间进展神经功能缺损症状逐渐加重,而CIR-3d组、CIR-7 d组神经功能缺损程度明显减轻。假手术组大鼠DWI和表观扩散系数图均无异常信号,CIR-1 h组DWI图像上存在高信号,其相应部位的相对表观扩散系数值明显下降;随着时间的增加,CIR-1 h组、CIR-3 h组、CIR-6 h组、CIR-12 h组、CIR-24 h组相对信号强度逐渐增高,在CIR-24 h时取得峰值; CIR-3 d组、CIR-7 d组DWI相对信号强度下降,但较假手术组仍明显升高。CIR-1 h组、CIR-3 h组、CIR-6 h组相对表观扩散系数逐渐下降,在CIR-6h时取得最低值,CIR-12 h组CIR-24 h组相对表观扩散系数有所下降,CIR-3 d组、CIR-7 d组相对表观扩散系数升高。TTC染色结果提示假手术组大鼠无梗死区域; CIR-1 h组出现右侧纹状体和周围小范围皮质梗死; CIR-3 h组、CIR-6 h组、CIR-12 h组、CIR-24 h组脑梗死区明显增多,CIR-7 d组脑梗死区明显缩小。HE染色结果可见CIR大鼠12 h皮质区和海马区发生缺血性损害,并且随着再灌注时间的延长损伤加重。结论大鼠CIRI后24 h内随着时间延长,脑损伤区DWI表观扩散系数逐渐下降,信号强度逐渐增强,而CIRI3 d后随着时间延长,脑损伤区DWI表观扩散系数逐渐升高,信号强度逐渐下降,提示通过DWI获取的表观扩散系数与信号强度对CIRI组织学特征的评估具有重要的临床意义,可直观显示CIRI后缺血区动态改变的情况。
Objective To analyze the changes of signal intensity and apparent diffusion coefficient of diffusion-weighted imaging( DWI) in brain injury area at different time after cerebral ischemia-reperfusion injury( CIRI) in rats. Methods 64 healthy adult male SD rats were randomly divided into sham-operated group and experimental group according to the principle of random allocation. According to the different time of cerebral ischemia-reperfusion( CIR),the experimental group was randomly divided into CIR-1 h group,CIR-3 h group,CIR-6 h group,CIR-12 h group,CIR-24 h group,CIR-3 d group and CIR-7 d group,with 8 rats in each group. CIR model of rats was established by modified suture embolism method. The degree of neurological impairment was evaluated by Zea Longa score. Coronal DWI scans were performed with 3. 0 T magnetic resonance scanner to measure the apparent diffusion coefficients and signal intensities of the infarcted lesions at basal nucleus level,and to calculate the relative apparent diffusion coefficients and signal intensities of the infarcted lesions. TTC staining was used to evaluate the volume of cerebral infarction in each group,and HE staining was used to observe the histomorphological changes of rats. Results After recovery from anesthesia,there was no neurological impairment in the sham-operated group,and neurological impairment in the CIR-1 h group was observed. The neurological impairment in the CIR-3 h group,CIR-6 h group,CIR-12 h group and CIR-24 h group was gradually aggravated,while the neurological impairment in the CIR-3 d group and CIR-7 d group was significantly alleviated. There were no abnormal signals in the DWI and apparent diffusion coefficient maps of rats in sham-operated group. There were high signals on the DWI images of CIR-1 h group,and the relative apparent diffusion coefficient values of the corresponding parts decreased significantly. With the increase of time,the relative signal intensity of CIR-1 h group,CIR-3 h group,CIR-6 h group and CIR-12 h group increased gradually,and reached the peak value at CIR-24 h. The relative reliability of DWI in CIR-3 d group and CIR-7 d group was higher than that in CIR-12 h group. The intensity of No. 1 decreased,but it was still significantly higher than that of sham-operated group. The relative apparent diffusion coefficients of CIR-1 h group,CIR-3 h group and CIR-6 h group decreased gradually,and reached the lowest value at CIR-6 h. The relative apparent diffusion coefficients of CIR-24 h group decreased,while the relative apparent diffusion coefficients of CIR-3 d group and CIR-7 d group increased. TTC staining showed that there was no infarct area in sham-operated group,right striatum and surrounding cortex infarction in CIR-1 h group,cerebral infarction area in CIR-3 h group,CIR-6 h group,CIR-12 h group and CIR-24 h group increased significantly,and cerebral infarction area in CIR-7 d group decreased significantly. HE staining showed that ischemic lesions occurred in the 12 h cortical and hippocampus of CIR rats,and the damage was aggravated with the prolongation of reperfusion time.Conclusion The apparent diffusion coefficient and signal intensity of DWI in brain injury area changed significantly at different time after CIRI in rats,suggesting that the apparent diffusion coefficient and signal intensity acquired by DWI have important clinical significance in evaluating the histological characteristics of CIRI and can visually show the dynamic changes of ischemic area after CIRI.
Objective To analyze the changes of signal intensity and apparent diffusion coefficient of diffusion-weighted imaging( DWI) in brain injury area at different time after cerebral ischemia-reperfusion injury( CIRI) in rats. Methods 64 healthy adult male SD rats were randomly divided into sham-operated group and experimental group according to the principle of random allocation. According to the different time of cerebral ischemia-reperfusion( CIR),the experimental group was randomly divided into CIR-1 h group,CIR-3 h group,CIR-6 h group,CIR-12 h group,CIR-24 h group,CIR-3 d group and CIR-7 d group,with 8 rats in each group. CIR model of rats was established by modified suture embolism method. The degree of neurological impairment was evaluated by Zea Longa score. Coronal DWI scans were performed with 3. 0 T magnetic resonance scanner to measure the apparent diffusion coefficients and signal intensities of the infarcted lesions at basal nucleus level,and to calculate the relative apparent diffusion coefficients and signal intensities of the infarcted lesions. TTC staining was used to evaluate the volume of cerebral infarction in each group,and HE staining was used to observe the histomorphological changes of rats. Results After recovery from anesthesia,there was no neurological impairment in the sham-operated group,and neurological impairment in the CIR-1 h group was observed. The neurological impairment in the CIR-3 h group,CIR-6 h group,CIR-12 h group and CIR-24 h group was gradually aggravated,while the neurological impairment in the CIR-3 d group and CIR-7 d group was significantly alleviated. There were no abnormal signals in the DWI and apparent diffusion coefficient maps of rats in sham-operated group. There were high signals on the DWI images of CIR-1 h group,and the relative apparent diffusion coefficient values of the corresponding parts decreased significantly. With the increase of time,the relative signal intensity of CIR-1 h group,CIR-3 h group,CIR-6 h group and CIR-12 h group increased gradually,and reached the peak value at CIR-24 h. The relative reliability of DWI in CIR-3 d group and CIR-7 d group was higher than that in CIR-12 h group. The intensity of No. 1 decreased,but it was still significantly higher than that of sham-operated group. The relative apparent diffusion coefficients of CIR-1 h group,CIR-3 h group and CIR-6 h group decreased gradually,and reached the lowest value at CIR-6 h. The relative apparent diffusion coefficients of CIR-24 h group decreased,while the relative apparent diffusion coefficients of CIR-3 d group and CIR-7 d group increased. TTC staining showed that there was no infarct area in sham-operated group,right striatum and surrounding cortex infarction in CIR-1 h group,cerebral infarction area in CIR-3 h group,CIR-6 h group,CIR-12 h group and CIR-24 h group increased significantly,and cerebral infarction area in CIR-7 d group decreased significantly. HE staining showed that ischemic lesions occurred in the 12 h cortical and hippocampus of CIR rats,and the damage was aggravated with the prolongation of reperfusion time.Conclusion The apparent diffusion coefficient and signal intensity of DWI in brain injury area changed significantly at different time after CIRI in rats,suggesting that the apparent diffusion coefficient and signal intensity acquired by DWI have important clinical significance in evaluating the histological characteristics of CIRI and can visually show the dynamic changes of ischemic area after CIRI.
引文
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[10]薛战尤,王安海,赵元,等.香芹酚通过MAPK/ERK信号通路对缺血再灌注后脑损伤大鼠的保护作用[J].临床和实验医学杂志,2018,17(23):2473-2476.
[11]He WM,Ying-Fu L,Wang H,et al.Delayed treatment ofα5GABAA receptor inverse agonist improves functional recovery by enhancing neurogenesis after cerebral ischemia-reperfusion injury in rat MCAO model[J].Sci Rep,2019,9(1):2287.
[12]Dreier JP,Lemale CL,Kola V,et al.Spreading depolarization is not an epiphenomenon but the principal mechanism of the cytotoxic edema in various gray matter structures of the brain during stroke[J].Neuropharmacology,2018,134(Pt B):189-207.
[13]Jiang CJ,Wang ZJ,Zhao YJ,et al.Erythropoietin reduces apoptosis of brain tissue cells in rats after cerebral ischemia/reperfusion injury:a characteristic analysis using magnetic resonance imaging[J].Neural Regen Res,2016,11(9):1450-1455.
[14]Viswanatha GL,Venkataranganna MV,Prasad NBL,et al.Achyranthes aspera Linn.alleviates cerebral ischemia-reperfusion-induced neurocognitive,biochemical,morphological and histological alterations in Wistar rats[J].J Ethnopharmacol,2019,228(1):58-69.
[15]姚胜旗,黄琼,许敏,等.左乙拉西坦对小鼠脑缺血再灌注损伤后Bax、Caspase-3表达的影响分析[J].临床和实验医学杂志,2018,17(17):1815-1818.
[2]Hur W,Kim BJ,Shin BS,et al.Discrepancy between perfusion-and diffusion-weighted images in ischemic stroke:A case report[J].Medicine(Baltimore),2018,97(52):e13894.
[3]Qian Q,Huang HT,Xu L,et al.Prediction of infarct lesion volumes by processing magnetic resonance apparent diffusion coefficient maps in patients with acute ischemic stroke[J].J Stroke Cerebrovasc Dis,2016,25(12):2821-2827.
[4]Takeshita S,Ogata T,Mera H,et al.Time course of diffusion weighted image and apparent diffusion coefficient in acute spinal cord infarction:A case report and review of the literature[J].Rinsho Shinkeigaku,2016,56(5):352-355.
[5]Singh V,Krishan P,Shri R.Antioxidant-mediated neuroprotection by Allium schoenoprasum L.leaf extract against ischemia reperfusion-induced cerebral injury in mice[J].J Basic Clin Physiol Pharmacol,2018,29(4):403-410.
[6]Song B,Cao Y,Pei L,et al.Efficacy of high-intensity statin use for transient ischemic attack patients with positive diffusion-weighted imaging[J].Sci Rep,2019,9(1):1173.
[7]Pei L,Song B,Fang H,et al.Combining diffusion-weighted imaging patterns with ABCD2 score predicts stroke risk after transient ischemic attack[J].Curr Neurovasc Res,2018,15(4):298-304.
[8]Aggarwal V,Sharma A,Sinha VD.Role of diffusion-weighted imaging in detecting early ischemic brain injury following aneurysmal subarachnoid hemorrhage[J].Asian J Neurosurg,2018,13(4):1074-1077.
[9]Sui HJ,Yan CG,Zhao ZG,et al.Prognostic value of diffusion-weighted imaging(DWI)apparent diffusion coefficient(ADC)in patients with hyperacute cerebral infarction receiving rt-PA intravenous thrombolytic therapy[J].Med Sci Monit,2016,22(1):4438-4445.
[10]薛战尤,王安海,赵元,等.香芹酚通过MAPK/ERK信号通路对缺血再灌注后脑损伤大鼠的保护作用[J].临床和实验医学杂志,2018,17(23):2473-2476.
[11]He WM,Ying-Fu L,Wang H,et al.Delayed treatment ofα5GABAA receptor inverse agonist improves functional recovery by enhancing neurogenesis after cerebral ischemia-reperfusion injury in rat MCAO model[J].Sci Rep,2019,9(1):2287.
[12]Dreier JP,Lemale CL,Kola V,et al.Spreading depolarization is not an epiphenomenon but the principal mechanism of the cytotoxic edema in various gray matter structures of the brain during stroke[J].Neuropharmacology,2018,134(Pt B):189-207.
[13]Jiang CJ,Wang ZJ,Zhao YJ,et al.Erythropoietin reduces apoptosis of brain tissue cells in rats after cerebral ischemia/reperfusion injury:a characteristic analysis using magnetic resonance imaging[J].Neural Regen Res,2016,11(9):1450-1455.
[14]Viswanatha GL,Venkataranganna MV,Prasad NBL,et al.Achyranthes aspera Linn.alleviates cerebral ischemia-reperfusion-induced neurocognitive,biochemical,morphological and histological alterations in Wistar rats[J].J Ethnopharmacol,2019,228(1):58-69.
[15]姚胜旗,黄琼,许敏,等.左乙拉西坦对小鼠脑缺血再灌注损伤后Bax、Caspase-3表达的影响分析[J].临床和实验医学杂志,2018,17(17):1815-1818.
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