促红细胞生成素上调海马pCREB表达和改善脑缺血小鼠认知功能

摘要

AIM: To investigate the neuroprotective effect of erythropoietin ( EPO ) on cognitive dysfunction and neuronal injury in hippocampal CA1 region induced by cerebral ischemia in mice.METHODS: Male C57BL/6 green fluorescent protein - transgenic mice were randomly divided into 3 groups: sham operation group ( sham ), ischemia/reperfusion group ( I/R ) and EPO - treated group.Transient cerebral global ischemia was induced by bilateral common carotid artery occlusion ( 2 - VO ).The step - down test was used to measure the capacity of learning and memory of the animals in each group.Nissl staining was applied to examine the neuronal number in hippocampal CA1 region.The expression of phosphorylated cAMP response element - binding protein ( pCREB ) was determined by Western blotting.Alterations of dendritic morphology in hippocampal CA1 region were evaluated using laser scanning confocal microscopy and Neurolucida software.RESULTS: Transient cerebral ischemia caused deficits of spatial learning and memory, and delayed neuronal death and loss of dendritic spines in hippocampal CA1 region were also obvious.The EPO treatment significantly improved the cognitive function in cerebral ischemic mice, and the protein expression of pCREB was obviously increased.At the same time, neuronal death and loss of dendritic spines were reduced in hippocampal CA1 region.CONCLUSION: Erythropoietin increases the protein expression of pCREB, and reduces neuronal death and loss of dendritic spines.These processes may be responsible for erythropoietin - mediated neuroprotective effects and the improvement of cognitive function in cerebral ischemic mice.%目的:探讨促红细胞生成素(EPO)对小鼠脑缺血所致的认知功能障碍和海马神经元损伤的保护作用及机制.方法:C57BL/6绿色荧光蛋白转基因小鼠随机分为假手术(sham)组、脑缺血/再灌注(I/R)组和EPO治疗组;采用双侧颈总动脉阻断(2-VO)方法复制小鼠全脑缺血模型,跳台实验测试小鼠学习记忆能力,Nissl染色检测海马神经元存活情况,Western blotting检测磷酸化cAMP反应元件结合蛋白(pCREB)表达水平,激光共聚焦显微镜和Neurolucida软件分析检测海马CA1区神经元形态及树突棘的变化.结果:脑缺血导致小鼠学习记忆能力下降,海马CA1区神经元迟发性死亡和树突棘丢失;EPO治疗能显著提高脑缺血小鼠的学习记忆能力,减少脑缺血所致的海马CA1区神经元死亡和树突棘的丢失,显著上调海马CA1区神经元pCREB蛋白的表达.结论:EPO可能通过上调pCREB的表达来保护神经元损伤、防止神经元树突棘的丢失,进而改善脑缺血小鼠的认知功能.