缺血后适应调控树鼩脑缺血海马CA1区Akt(pS473)和Akt(pT308)过磷酸化的抗凋亡机制  

Mechanism of ischemic postconditioning regulated Akt(pS473) and Akt(pT308) hyperphosphorylation and neuronal apoptosis in hippocampal CA1 area after cerebral ischemia in tree shrew

作　　者：汤諹[1] 李树清[2] TANG Yang LI Shu-qing(Department of Dermatology, the First Affiliated Hospital, Kunming Medical University, Kunming 650032, China Department of Pathophysiology , Kunming Medical University, Kunming 650500, China)

机构地区：[1]昆明医科大学第一附属医院皮肤科,昆明650032 [2]昆明医科大学病理生理学教研室,昆明650500

出　　处：《解剖学报》2016年第5期591-598,共8页Acta Anatomica Sinica

基　　金：国家科技支撑计划(2014BAI01B01);国家自然科学基金(30971171)

摘　　要：目的观察树鼩脑缺血海马神经元Akt(p S473)和Akt(p T308)磷酸化改变对CA1区细胞凋亡的影响,探讨缺血后适应(PC)抑制细胞凋亡的可能机制。方法用光化学诱导法诱导树鼩脑缺血并建立缺血PC模型;用免疫组织化学TACS原位凋亡检测试剂盒检测皮层及海马CA1区神经元凋亡数量,用免疫组织化学法检测Akt(p S473)和Akt(p T308)表达的空间分布,用ELISA法检测海马CA1区神经元Akt(p S473)和Akt(p T308)磷酸化水平;用电子显微镜观察其神经元超微结构改变。结果脑缺血后神经元皱缩,核消失以缺血24h为著。脑缺血后4 h、24 h及72 h皮层及海马CA1区神经元TUNEL阳性细胞数明显增加(P<0.01),海马CA1区神经元Akt(p S473)和Akt(p T308)的表达及磷酸化水平明显升高,以脑缺血4 h的改变最明显,分别为(152.3±3.5)units/mg、(130.8±2.6)units/mg和(149.5±4.7)units/mg和(42.35±2.49)units/mg、(19.23±1.41)units/mg和(23.38±1.32)units/mg(P<0.01)。缺血PC组神经元损伤明显减轻,皮层及海马CA1区TUNEL阳性细胞明显减少(P<0.01),且与海马神经元Akt(p T308)活化水平呈平行改变(P<0.05)。结论树鼩脑缺血海马CA1区细胞凋亡与Akt(p S473)和Akt(p T308)过磷酸化的信号机制有关,缺血PC抑制海马神经元Akt(p S473)和Akt(p T308)双磷酸化可能具有抗凋亡作用。Objective To investigate the effects of Akt（ p S473） and（ p T308） phosphorylation on neurons apoptosis in hippocampal CA1 area after thrombotic cerebral ischemia, and to explore the possible mechanisms of ischemic postconditioning（ PC） for inhibiting neuron apoptosis. Methods Thrombotic cerebral ischemia was induced by photochemical reaction and an ischemic PC model was established in tree shrews. The expression and phosphorylation of Akt（ p S473） and Akt（ p T308） in hippocampus CA1 area were determined,respectively,by immunohistochemistry and ELISA. The neuron apoptosis was detected by a kits-detection of immunohistochemistry TACS in situ. Ultrastructures of cortex and hippocampal neurons were abserved under an electron microscope. Results The neurons shrinkaged,nuclear disappear in 24 hours after cerebral ischemia. The expression and phosphorylation levels of Akt（ p S473） and Akt（ p T308） in hippocampal CA1 area were significantly higher [Akt（ p S473） ：（ 152. 3 ± 3. 5） units / mg,（ 130. 8 ± 2. 6） units / mg and（ 149. 5 ± 4. 7） units/mg and AKT（ p T308） ：（ 42. 35 ± 2. 49） units/mg,（ 19. 23 ± 1. 41） units/mg and（ 23. 38 ± 1. 32）units / mg,respectively,（ P〈0. 01） ] than the control group,and the counts of TUNEL positive cells in hippocampal CA1 area were increased significantly than the control group（ P〈0. 01） in the ischemic group in different time points,but theless TUNEL positive neurons decreased significantly（ P〈0. 01）. Neuron injury was reduced significantly in the ischemia PC group,and this change coincided with the level of Akt（ p S473） and Akt（ p T308） activation. Conclusion The level of phosphorylation of Akt（ p S473） and Akt（ p T308） is closely related to the neuron apoptosis of hippocampal CA1 area after brain ischemia in tree shrews,and the mutual phosphorylation of Akt（ p S473） and Akt[p T308]exerts an important role in inhibition of hippocampal cell apoptosis after ischemic PC treatment.

关 键 词：脑缺血 后适应 海马 AKT磷酸化 信号转导 光化学 树鼩 

分 类 号：R743.3[医药卫生—神经病学与精神病学]