Abstract
Objective
To investigate whether desferoxamine (DFO) preconditioning can induce tolerance against cerebral ischemia and its effect on the expression of hypoxia inducible factor 1α (HIF-1α) and erythropoietin (EPO) in vivo and in vitro.
Methods
Rat model of cerebral ischemia was established by middle cerebral artery occlusion with or without DFO administration. Infarct size was examined by TTC staining, and the neurological severity score was evaluated according to published method. Cortical neurons were cultured under ischemia stress which was mimicked by oxygen-glucose deprivation (OGD), and the neuron damage was assessed by MTT assay. Immunofluorescent staining was employed to detect the expressions of HIF-1α and EPO.
Results
The protective effect induced by DFO (decreasing the infarction volume and ameliorating the neurological function) appeared at 2 d after administration of DFO (post-DFO), lasted until 7 d and disappeared at 14 d (P < 0.05); the most effective action was observed at 3 d post-DFO. DFO induced tolerance of cultured neurons against OGD: neuronal viability was increased 23%, 34%, 40%, 48% and 56% at 8 h, 12 h, 24 h, 36 h, and 48 h, respectively, post-DFO (P < 0.05). Immunofluorescent staining found that HIF-1α and EPO were upregulated in the neurons of rat brain at 3 d and 7 d post-DFO; increase of HIF-1α and EPO appeared in cultured cortex neurons at 36 h and 48 h post-DFO.
Conclusion
DFO induced tolerance against focal cerebral ischemia in rats, and exerted protective effect on OGD cultured cortical neurons. DFO significant induced the expression of HIF-1α and EPO both in vivo and in vitro. DFO preconditioning can protect against cerebral ischemia, which may be associated with the synthesis of HIF-1α and EPO.
Keywords: desferoxamine, ischemia preconditioning, hypoxia inducible factor 1α, erythropoietin
摘要
目的
观察去铁敏(Desferoxamine, DFO) 预处理后大鼠脑组织和体外培养神经元中缺氧诱导因子1α (hypoxia inducible factor 1 α, HIF-1g) 和促红细胞生成素 (erythropoietin, EPO) 表达的变化, 探讨预处理是否对体内及体外的脑缺血损伤的具有保护效应.
方法
去铁敏预处理大鼠后不同时间点制作大脑中动脉阻죻 (middle cerebral artery occlusion, MCAO) 模型, 术后24 h 后处死动物. 采用神经功能评分 (neurological severity scores, NSS) 和计算梗死体积 (TTC 染色) 评价DFO 的脑保护效应, 细胞活力测定评价DFO 对缺氧缺糖条件下 (oxygen-glucose deprivation, OGD) 皮层神经元的保护效应.免疫荧光染色检测HIF-1α 和EPO 蛋白表达情况.
结果
与生理盐水对照组比较, 去铁敏预处理后2 d, MCAO 大鼠出现梗 塞面积缩小, 神经功能损伤减轻, 在预处理后3 d 达到高峰, 7 d 仍然有效, 14 d 去铁敏预处理的保护效应消失.去铁敏对OGD 神经元同样具有神经保护作用, 与未进行预处理的神经元细胞相比, 预处理后8 h 的细胞活力增加 23%, 12 h 增加34%, 24 h 增加40%, 36 h 增加48%, 48 h 增加56% (P < 0.05). 免疫荧光染色发现, 大鼠脑组织的HIF-1α 和EPO在去铁敏预处理后3 d 及7 d 表达上调, 皮层神经元细胞的HIF-1 和EPO在去铁敏预处理后36 h 及48 h表达上调.
结论
去铁敏预处理有确切有效的脑保护效应, 不仅可以预防脑缺血损伤, 对体外培养的OGD皮层神经元细胞损伤也具有保护作用, 其机制可能与脑神经细胞的HIF-1α 和EPO 蛋白表达增加有关.
关键词: 去铁敏, 缺血预适应, 缺氧诱导因子1α, 促红细胞生成素
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