高血糖经抑制磷酸化腺苷酸活化蛋白激酶加重脑缺血再灌注损伤

目的:探讨磷酸化的腺苷酸活化蛋白激酶(p-AMPK)在高血糖加重脑缺血再灌注损伤中的作用。方法:通过注射链脲佐菌素制备糖尿病高血糖模型,线栓法制备大脑中动脉阻塞(MCAO)再灌注模型;分为假手术组(sham组),正常血糖脑缺血再灌注24 h组(NM I/R 24 h组)、72 h组(NM I/R 72 h组),高血糖脑缺血再灌注24 h组(HM I/R 24 h组)以及72 h组(HM I/R 72 h组),采用组织学、免疫组织化学及免疫印迹等方法,比较观察脑组织的损伤及p-AMPK的表达。结果:NM I/R 24 h组、NM I/R 72 h组大鼠均可见神经功能缺失的表现,HM组大鼠神经功能缺失评分明显高于NM组。NM I/R 24 h组梗死区脑组织疏松水肿,神经元固缩;HM组大鼠脑组织疏松水肿及固缩神经元较NM组大鼠明显增加;与NM I/R 72 h组比较,HM组大鼠仍存在脑组织疏松水肿,较多固缩神经元。免疫组织化学显色和免疫印迹结果可见,I/R 24 h和I/R 72 h,HM组p-AMPK相对蛋白量明显低于NM组。p-AMPK定位观察可见,p-AMPK与神经元共表达,但不与星形胶质细胞共表达。结论:糖尿病高血糖加重大鼠局灶性脑缺血再灌注损伤,可能与神经元磷酸化腺苷酸活化蛋白激酶减少有关。

Hyperglycemia aggravates ischemic/reperfused brain injury by inhibiting phosphorylated AMP-activated protein kinase

Objective : To explore the role of phosphorylated AMP-activated protein kinase(p-AMPK) in hyperglycemiaaggravated cerebral ischemia-reperfusion injury. Methods :Hyperglycemia was induced by streptozotocin. The focal cerebral I/R was made by middle cerebral artery occlusion(MCAO) with suitable thread. The rats were divided into sham group(sham), normoglycemic ischemia-reperfusion 24 h group(NM I/R 24 h), and normoglycemic ischemia-reperfusion72 h group(NM I/R 72 h), hyperglycemic ischemia-reperfusion 24 h group(HM I/R 24 h), and hyperglycemic ischemiareperfusion 72 h group(HM I/R 72 h). The histopathology and the expression of p-AMPK in the brain were comparatively studied using histology, immunohistochemistry and Western blotting. Results : After ischemia for 30 min and reperfusion at24 h and 72 h, obvious neurological deficits appeared in the rats of NM group. Compared with NM group, the neurological deficit scores in HM group was significantly increased. Rats in NM group were treated with 30 min ischemia and reperfused at 24 h, the edema, swollen-neuron, and neural pyknosis in the ischemic regions appeared at 72 h reperfusion, the edema was decreased, but the pyknosis was still increased. Compared with NM group, the edema and neural pyknosis in HM group were significantly increased at 24 h or 72 h reperfusion. The Western blotting and immunohistochemistry of p-AMPK showed that a significant decrease of p-AMPK was demonstrated in the HM group in comparison with the NM group. The expression of p-AMPK was located in the neurons rather than astrocytes. Conclusion : Diabetic hyperglycemia aggravates focal cerebral ischemia-reperfusion injury in the rats, and it may be involved in decreased phosphorylated AMP-activated protein kinase in neurons.