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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-1α)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塞(middle cerebral artery occlusion,MCAO)模型,术后24h后处死动物。采用神经功能评分(neurological se-verity 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2d,MCAO大鼠出现梗塞面积缩小,神经功能损伤减轻,在预处理后3d达到高峰,7d仍然有效,14d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8h的细胞活力增加23%,12h增加34%,24h增加40%,36h增加48%,48h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3d及7d表达上调;皮层神经元细胞的HIF-1α和EPO在去铁敏预处理后36h及48h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。
Objective To observe the expression of hypoxia inducible factor 1α (HIF-1α) and erythropoietin (EPO) in rat brain tissue and in vitro cultured neurons after desferoxamine (DFO) pretreatment To investigate whether pretreatment has a protective effect on cerebral ischemia injury in vivo and in vitro. Methods The MCAO model was made at different time points after dextran preconditioning, and animals were sacrificed 24h after the operation. The protective effect of DFO was evaluated by neurological se-verity scores (NSS) and infarction volume (TTC staining), and cell viability assay was used to evaluate the effect of DFO on oxygen-glucose deprivation (OGD) Meta-protection effect. Immunofluorescence staining was used to detect the expression of HIF-1αand EPO protein. Results Compared with the saline control group, infarction size and nerve function impairment of MCAO rats were reduced 2 days after pretreated with deferoxamine, peaked at 3d after pretreatment, and remained effective for 7 days. The protective effect of desferoxamine pretreatment disappear. Deferoxamine also had neuroprotective effects on OGD neurons: compared with non-pretreated neurons, cell viability increased by 23% at 8h, increased by 12% at 12h, increased by 40% at 24h, and increased by 48% at 36h , 48h increased 56% (P <0.05). Immunofluorescence staining showed that HIF-1αand EPO in rat brain were upregulated at 3d and 7d after deferoxamine pretreatment; HIF-1α and EPO in cortical neurons were up-regulated at 36h and 48h after deferoxamine pretreatment . Conclusion Dextrin pretreatment has an effective and effective brain protective effect, which can not only prevent cerebral ischemia injury, but also protect the cultured OGD cortical neurons from damage. The mechanism may be related to the decrease of HIF-1α and EPO Increased protein expression.