亚低温后适应对树鼩局部脑缺血海马CA1区神经元的保护机制  

Hypothermia postconditioning protects hippocampal CA1 neurons from focal cerebral ischemia in tree shrew

作　　者：李飞[1] 李树清[1] 

机构地区：[1]昆明医学院病理生理学教研室,云南昆明650031

出　　处：《中国病理生理杂志》2009年第2期236-240,共5页Chinese Journal of Pathophysiology

基　　金：国家自然科学基金资助项目(No.30660056);教育部博士点专项基金资助项目(No.20050678008);云南省自然科学基金资助项目(No.2004C0043M)

摘　　要：目的:观察亚低温后处理(HPC)对树鼩局部脑缺血后不同时间海马CA1区血管内皮生长因子(VEGF)表达及神经元缺失的影响,探讨亚低温后适应保护脑缺血后海马CA1区神经元的可能机制。方法:建立光化学诱导树鼩脑缺血模型,于缺血后6h采用局部恒温控温装置使脑温降低并维持亚低温(31-32℃)状态1h。用免疫组化法及图像分析仪测定海马CA1区VEGF表达的改变;计数海马神经元并观察其超微结构变化。结果:与常温组相比,亚低温后适应组海马CA1区VEGF表达在24h时增加而72h时明显下降(P<0.01);24h时神经元坏死减少,72h时坏死细胞增多,缺血侧超微结构呈现相同变化。结论:在脑缺血后早期VEGF的表达可能与其直接发挥对神经元细胞的保护作用有关,亚低温后适应对脑缺血的保护作用在脑缺血的早期有明显意义,而在缺血的晚期则可能加重脑缺血的损伤,低温后适应脑保护的意义在于延长脑缺血治疗时间窗。AIM： To observe the changes in vascular endothelial growth factor （VEGF） expression and the cell numbers of cellular necrosis in hippocampus CA1 area after cerebral ischemia and hypothermia postconditioning （HPC）. METHODS： The focal thrombotic cerebral ischemia was induced by photochemical reaction in tree shrews. 6 h after ischemia, HPC was executed by a focal homoeothermic equipment, which reduced the brain temperature and maintained at 31 -32℃ for 1 h. VEGF expression in hippocampus CA1 area was detected by immunohistochemistry. The numbets of death cells were counted and the ultrastructure was observed under the electron microscope. RESULTS： Compared to control group, VEGF expressions increased in neuron of hippocampus CA1 area at 24 h, and decreased at 72 h in HPC group （P〈0. 01 ）. Meanwhile the numbers of necrotic cells reduced at 24 h, and increased at 72 h. In accordance with this, uhrastructure of mitochondrion and endoplasmic reticulum became deterioration at 72 h. CONCLUSION ： During the early stage, VEGF expression maybe directly protects neurons from cerebral ischemia. HPC has a remarkable significance to neuroprotective function in this time, but it may aggravate neuron injury in the last stage of cerebral ischemia. The HPC may prolong the treatment time - windows in the acute phase of cerebral ischemia.

关 键 词：光化学 脑缺血 血管内皮生长因子 低温后处理 

分 类 号：R363[医药卫生—病理学]