亚低温调控冷休克蛋白CIRBP、RMB3影响心脏骤停复苏后神经再生作用机制的研究

Patients resuscitated from cardiac arrest are often left with neurologic impairments. Strateies for improving outcome after cardiac arrest include reducing acute brain damage and promoting neuroplasticity. Recent clinical studies have established a role for hypothermia therapy in neuroprotection in anoxic brain injury due to cardiac arrest, but the influence of hypothermia on neurogenesis following cardiac arrest is not clear. In order to clarify the influence of mild hypothermia therapy on neurogenesis and its mechanism in brain following cardiac arrest resuscitation, we will study mild hypothermia influences on neurogensis and neurologic function following cardiac arrest in rat model with Brdu (bromodeoxyuridine) label, immunohistochemistry and behavioral assessment. We will also detect cold-shock protein such as CIRP(cold-inducible RNA binding protein) and RBM3(RNA binding motif protein3) expression in mRNA and protein level in rat cardiac arrest model following mild hypothermia therapy. The cold-shock protein expression and their influence on stem cell proliferation and apoptosis will be detected in cultured primary neural stem cells ,PC12 cells and other cell lines with stem cell characters , these cells will be cultured until planed point following hypoxia and mild hypothermia culture. The retrovirus vectors overexpressing CIRP and RBM3 will be constructed . For down regulation of CIRP and RBM3 the special siRNA sequence against CIRP and RBM3 will be used. The association between cold-shock protein and stem cell proliferation will be observed in cultured cells which were transfected with retrovirus vectors or siRNA sequence. We will continue to detect the proteins expression associated with signal transduction pathway ERK1/2(extracellar signal regulated kinase 1 and 2) and CIRP/RBM3 expression in different cell lines treated with mild hypothermia. This study will prove mild hypothermia could promote endogenous neurogenesis following cardiac arrest through raising cold-shock protein CIRP/RBM3 expression and signal transduction pathway ERK1/2 activation.

为阐明亚低温治疗对心脏骤停心肺复苏后神经再生的影响及其机制。本研究首先建立心脏骤停心肺复苏大鼠模型，采用Brdu标记、免疫组化、行为学测试等方法，证实亚低温治疗具有促进心脏骤停后神经再生和改善神经功能的作用，再采用RT-PCR、蛋白免疫印迹技术观察亚低温治疗后冷休克蛋白CIRP、RBM3在mRNA 和蛋白水平的表达。然后从细胞水平观察亚低温对缺氧处理神经干细胞及PC12等具有干细胞特性细胞冷休克蛋白表达，以及对干细胞增殖、凋亡的影响。采用逆转录病毒、siRNA、细胞转染技术过表达或抑制冷休克蛋白的表达，阐明冷休克蛋白与神经干细胞增殖和凋亡的关系。进一步观察亚低温治疗后CIRP、RBM3与信号传导通路ERK1/2相关蛋白的表达，揭示亚低温促进神经干细胞增殖的信号通路。通过本研究将阐明亚低温增加冷休克蛋白CIRP、RBM3表达、激活ERK1/2信号通路，促进心脏骤停后内源性神经再生的作用机制。

心脏骤停是引起人类死亡的主要原因，心脏骤停复苏成功后患者神经功能的恢复是心脏骤停患者成功救治的关键。临床研究表明亚低温治疗是改善心脏骤停患者存活和神经功能预后的唯一有效方法。低温治疗可以减低氧耗和代谢速率，减少血流，减少凋亡等发挥神经保护作用。内源性神经干细胞在心肺复苏术后的作用受到越来越多的重视，低温治疗对心肺复苏术后内源性神经干细胞是否具有影响是本研究的重点。本课题采取动物实验和细胞试验对低温治疗对心肺复苏术后动物及细胞模型内源性神经干细胞的增殖、分化等进行了研究。通过窒息法建立了心脏骤停心肺复苏大鼠模型，采用Brdu 标记、免疫组化、行为学测试等方法，证实亚低温治疗具有改善神经功能的作用，其作用与促进心脏骤停后神经再生有关。然后以原代培养的神经干细胞为研究对象，采用RT-PCR、蛋白免疫印迹技术发现给予低温缺氧处理后神经干细胞冷休克蛋白CIRP、RBM3表达增加。再采用采用慢病毒、siRNA、细胞转染技术抑制冷休克蛋白的表达，研究发现抑制抑制CIRP表达后，检测AKT表达下调，p-AKT表达上调，p-ERK1+p-ERK2表达明显下调，说明抑制CIRP的表达减少了ERK1/2的表达，从而影响增殖相关基因蛋白的表达。本研究还需进一步对相关机制进行进一步研究和探讨，从而为心肺复苏术后脑功能的复苏提供更多的理论依据。