目的观察大鼠大脑皮层梗死后丘脑腹后外侧核(ventroposterior nucleus of the thalamus,VPN)的继发性损害是否有DNA氧化损伤,并研究抗氧化剂依布硒啉(ebselen,EB)对这种远隔部位损伤是否具有改善作用。方法采用易卒中型肾血管性高血压大...目的观察大鼠大脑皮层梗死后丘脑腹后外侧核(ventroposterior nucleus of the thalamus,VPN)的继发性损害是否有DNA氧化损伤,并研究抗氧化剂依布硒啉(ebselen,EB)对这种远隔部位损伤是否具有改善作用。方法采用易卒中型肾血管性高血压大鼠(stroke-prone renovascular hypertensive rats,RHRSP),建立大脑中动脉皮层支闭塞(middle cerebral artery occlusion,MCAO)模型后分为:①假手术组,②模型组,③溶剂组,④抗氧化剂EB10mg.kg-1组,⑤抗氧化剂EB30mg.kg-1组,每组5只大鼠。2周后行肢体运动神经功能评估并取VPN后行尼氏染色,免疫组化检测VPN的8-羟基-2-脱氧马苷(8-hydroxy-2-deoxyguanosine,8-ohdG)表达。结果EB10mg.kg-1组和EB30mg.kg-1组神经功能评分优于假手术组(1.80±0.56,1.72±0.48vs2.28±0.33,P<0.05)。尼氏染色可见假手术组同侧VPN细胞形态规整。而梗死同侧VPN神经细胞出现细胞体积变小,胞核固缩,尼氏体退变为萎缩的深色细胞。EB30mg.kg-1组尼氏染色观察到改善作用。溶剂组同侧VPN的8-ohdG阳性细胞数目(0.1mm2)显著增加(146.8±12.1vs108.4±19.2,P<0.05);与溶剂组相比,EB10mg.kg-1组和EB30mg.kg-1组阳性细胞数目显著下降(123.6±14.7,123.4±17.4vs146.8±12.1,P<0.05)。结论实验性大脑皮层梗死后2周,同侧VPN存在DNA氧化性损伤。抗氧化剂EB对VPN的DNA氧化损伤有抑制作用,并可改善神经功能。展开更多
BACKGROUND： Following ischemia, apoptosis is observed at the ipsilateral ventropostenor thalamic nucleus and substantia nigra, which are distant from, but connected to, the ischemic cerebral cortex, in animals with n...BACKGROUND： Following ischemia, apoptosis is observed at the ipsilateral ventropostenor thalamic nucleus and substantia nigra, which are distant from, but connected to, the ischemic cerebral cortex, in animals with normotension. However, secondary brain damage in hypertension has not been clearly investigated. OBJECTIVE： The present study determined whether neuronal apoptosis is associated with neuronal loss in the ipsilateral ventroposterior thalamic nucleus and substantia nigra following cortical ischemia in adult hypertensive rats. Results should provide options for determining a time window for anti-apoptotic therapy. DESIGN, TIME AND SETTING： All experimental procedures in this randomized, controlled trial were conducted at the Neurological Laboratory of the First Affiliated Hospital of Sun Yat-sen University of China between October 2006 and July 2008. MATERIALS： Monoclonal primary antibodies specific to mouse anti-rat microtubule-associated protein 2 and glial fibrillary acidic protein were respectively purchased from Sigma Chemical, USA and BD Pharmingen, USA. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labeling （TUNEL） detection kits were purchased from Roche Applied Science, Switzerland and Upstate, USA, respectively. METHODS： A total of 64 male, Sprague Dawiey rats, aged 60-90 days, were equally and randomly divided into middle cerebral artery occlusion and sham surgery groups. Renovascular hypertension was established in both groups by renal artery occlusion. Right distal middle cerebral artery occlusion was performed by electrocoagulation in the middle cerebral artery occlusion group. MAIN OUTCOME MEASURES： Microtubule-associated protein 2 and glial fibrillary acidic protein were detected by immunohistochemistry, and apoptotic cells were observed by TUNEL assay. The stainings were separately detected in the ipsilateral ventroposterior thalamic nucleus and substantia nigra. RESULTS： During the 4 weeks following distal middle cerebral artery occlusion in renovascular hypertensive rats, microtubule-associated protein 2 expression gradually, but significantly, decreased （P 〈 0.05）. Expression of glial fibrillary acidic protein increased significantly in the ipsilateral ventroposterior thalamic nucleus and substantia nigra （P 〈 0.05） and reached a peak at 4 weeks. In addition, number of apoptotic cells was significantly increased in both areas compared with the sham controls （P 〈 0.05）, with a peak at 2 weeks. CONCLUSION： Results suggested that neuronal loss in the ipsilateral ventroposterior thalamic nucleus and substantia nigra following distal middle cerebral artery occlusion in hypertensive rats could be a secondary event resulting from apoptosis. The temporal apoptosis profile provides options for determining a time window for anti-apoptotic therapy at 2 weeks after stroke.展开更多
基金Chinese Medical Board of USA, No.CMB00-730the Na-tional Natural Science Foundation of China, No. 30770764, 30973108the Fund of Health Department of Guangdong Province Department of China, No.A2009172
文摘BACKGROUND： Following ischemia, apoptosis is observed at the ipsilateral ventropostenor thalamic nucleus and substantia nigra, which are distant from, but connected to, the ischemic cerebral cortex, in animals with normotension. However, secondary brain damage in hypertension has not been clearly investigated. OBJECTIVE： The present study determined whether neuronal apoptosis is associated with neuronal loss in the ipsilateral ventroposterior thalamic nucleus and substantia nigra following cortical ischemia in adult hypertensive rats. Results should provide options for determining a time window for anti-apoptotic therapy. DESIGN, TIME AND SETTING： All experimental procedures in this randomized, controlled trial were conducted at the Neurological Laboratory of the First Affiliated Hospital of Sun Yat-sen University of China between October 2006 and July 2008. MATERIALS： Monoclonal primary antibodies specific to mouse anti-rat microtubule-associated protein 2 and glial fibrillary acidic protein were respectively purchased from Sigma Chemical, USA and BD Pharmingen, USA. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labeling （TUNEL） detection kits were purchased from Roche Applied Science, Switzerland and Upstate, USA, respectively. METHODS： A total of 64 male, Sprague Dawiey rats, aged 60-90 days, were equally and randomly divided into middle cerebral artery occlusion and sham surgery groups. Renovascular hypertension was established in both groups by renal artery occlusion. Right distal middle cerebral artery occlusion was performed by electrocoagulation in the middle cerebral artery occlusion group. MAIN OUTCOME MEASURES： Microtubule-associated protein 2 and glial fibrillary acidic protein were detected by immunohistochemistry, and apoptotic cells were observed by TUNEL assay. The stainings were separately detected in the ipsilateral ventroposterior thalamic nucleus and substantia nigra. RESULTS： During the 4 weeks following distal middle cerebral artery occlusion in renovascular hypertensive rats, microtubule-associated protein 2 expression gradually, but significantly, decreased （P 〈 0.05）. Expression of glial fibrillary acidic protein increased significantly in the ipsilateral ventroposterior thalamic nucleus and substantia nigra （P 〈 0.05） and reached a peak at 4 weeks. In addition, number of apoptotic cells was significantly increased in both areas compared with the sham controls （P 〈 0.05）, with a peak at 2 weeks. CONCLUSION： Results suggested that neuronal loss in the ipsilateral ventroposterior thalamic nucleus and substantia nigra following distal middle cerebral artery occlusion in hypertensive rats could be a secondary event resulting from apoptosis. The temporal apoptosis profile provides options for determining a time window for anti-apoptotic therapy at 2 weeks after stroke.
