促红细胞生成素经EPOR/PI3K/Akt信号通路调控早产儿脑白质损伤血管修复的机制研究

Periventricular white matter injury（WMI） is the most important of premature infant brain injury. Yet, no targeted therapy for WMI is presently available. Our research confirmed that EPO has protection effect to the WMI model mouse. And EPO increased the angiogenesis in the injured brain.However， its mechanism is unclear. We further found that EPO increased the EPO receptor (EPOR) and phosphorylated Akt in experimental rat models of WMI. But，it did not affect the expression of EPOR besides angiogenesis after using the PI3K inhibitors. Accordingly，we suggest that EPO binding of EPOR, which results in acting on the downstream of PI3K/Akt signaling transduction. It maybe mediates vascular repair through this signal channels. Adopting overexpression/knock down strategies in endothelial cells and inhibit strategies in neonatal rats, we intend to explicit the changes of key protein, upstream of EPOR and downstream of Akt key role in signaling transduction of EPO to regulate angiogenesis. So far, there is no report of the mechanism of EPO regulate vascular repair in premature WMI. And it may provide new clues of neuroprotection for EPO, especially in EPO treatment of premature WMI. This study is the foundation of state funds to encourage eugenics innovative research.

脑白质损伤（WMI）是早产儿最重要的脑损伤，目前无有效防治方法。我们研究证实EPO对WMI模型鼠脑具有良好保护作用，且EPO干预WMI模型鼠脑组织区出现血管生成，但其机制不清楚。我们进一步发现，EPO干预后脑组织区EPO受体（EPOR）和磷酸化的Akt表达上升，运用PI3K抑制剂未影响到EPOR的表达但血管生成减少。据此，我们设想EPO经EPOR/PI3K/Akt这一信号传导调控受损脑组织区血管修复。本研究拟从内皮细胞到新生大鼠，在细胞层面通过基因转染及SiRNA基因沉默技术、动物模型层面通过EPOR拮抗剂和PI3K抑制剂分别对上下游信号关键蛋白进行干预，探讨不同浓度EPO对信号传导中EPOR和Akt蛋白表达及EPOR/PI3K/Akt信号传导的改变对EPO调控血管新生的影响。EPO干预早产儿WMI血管修复的机制未见报道，本研究将为阐明EPO在早产儿WMI中的神经保护机制提供新的线索。

目的：探讨EPO干预早产儿WMI中通过EPO/PI3K/Akt这一信号途径调控受损脑组织区血管修复的机制。主要利用在体观察，分为三大部分实验，首先观察EPO应用后对早产儿脑损伤ROP的影响；随后从正反两方面观察EPO对信号传导中关键蛋白（EPOR和Akt）表达的影响，初步获得EPOR和Akt在EPO调控血管修复机制通路中的上下游关键作用的分子机制；最后从正反两方面观察 EPO 对血管修复关键细胞内皮细胞、促血管生长因子及微小血管的变化，进一步验证EPOR/PI3K/Akt 信号传导在EPO调控血管修复中的机制。结果： 1）本实验初步验证在应用EPO治疗后，并不会对早产儿脑损伤的视网膜造成进一步影响。2）EPO与EPOR作用可影响下游信号通路蛋白，增加脑组织中血管生成因子的表达。3）EPO可通过激活PI3K/Akt信号通路促进早产儿脑损伤模型损伤脑区血管生成因子的表达，参与促进损伤脑区的血管新生反应。意义：本研究创新从血管角度深度探讨EPO对早产儿WMI的保护作用。通过研究，我们发现EPO干预早产儿脑损伤可以通过EPOR/PI3K/Akt信号传导促进血管修复，这为临床中早产儿脑损伤的救治提供了新思路，同时也为EPO在非造血系统疾病中的应用研究提供新方向。