【作者】 朱军；

【导师】 陈罡；

【作者基本信息】 苏州大学 ， 神经外科， 2018， 硕士

【摘要】 目的蛋白激酶C受体1(Receptor for activated protein kinase C 1,RACK1)是一种多维支架蛋白,其在神经元保护过程中参与调节相关信号传导活动。在本文中,笔者主要研究RACK1在大鼠创伤性脑损伤(TBI)模型继发性脑损伤中所发挥的作用。方法实验采用落重法建立Sprague Dawley大鼠TBI损伤模型,并在模型建立24小时前实施RACK1体内表达降低和过表达。TBI损伤实施1小时后,以侧脑室注射方式施用IRE1抑制剂3,5-二溴水杨醛(3,5-dibromosalicylaldehyde,DBSA)。采用实时PCR、蛋白质印迹法、免疫荧光检验法、观察神经元凋亡情况、检测脑含水量和神经功能评分等方法观测实验。结果TBI诱导引起了神经元内多种蛋白质的表达水平上调,这些蛋白质包括:内源性RACK1、磷酸化肌醇需求激酶1(p-IRE1)、X盒连接蛋白1(XBP1)和葡萄糖调节蛋白78(GRP78)。随着p-IRE1、XBP1和GRP78表达的上调,RACK1过表达显著缓解了TBI模型建立48小时后的神经元细胞凋亡、血脑屏障破坏、脑水肿和神经缺陷情况,而其降低则诱导相反的结果。此外,DBSA给药可逆转RACK1过表达对脑损伤的保护作用,降低p-IRE1、XBP1和GRP78的表达水平。简言之,颅脑损伤后RACK1上调引发了对继发性脑损伤的神经保护作用,这可能是由IRE1-XBP1通路的激活介导的。更多还原

【Abstract】 Objective Receptor for activated protein kinase C 1(RACK1)is a multifaceted scaffolding protein known to be involved in the regulation of signaling events required for neuronal protection.In the present study,weinvestigated the role of RACK1 in secondary brain injury in a rat traumatic brain injury(TBI)model.Method A weight-drop TBI model was established in Sprague Dawley rats,and RACK1 in vivo knockdown and overexpression were performed 24 hours before TBI insult.The IRE1 inhibitor 3,5-dibromosalicylaldehyde(DBSA)was administered by intracerebroventricular injection 1 hour after TBI insult.Real-time PCR,Western blotting,immunofluorescence,neuronal apoptosis,brain water content,and neurological scores we re evaluated.Results Our results revealed that TBI induced increased expression of endogenous RACK1,phosphorylated inositol-requiring enzyme 1(p-IRE1),X-boxbinding protein-1(XBP1)and glucose-regulated protein 78(GRP78)in neurons.RACK1 overexpression significantly ameliorated neuronal apoptosis,blood-brain barrier disruption,brain edema and neurological deficits at 48 hours after TBI,which was concomitant with upregulation of p-IRE1,XBP1 and GRP78 expression,while its knockdown induced the opposite effects.Furthermore,DBSA administration reversed the protective effects of RACK1 overexpression against brain injury and decreased the expression of p-IRE1,XBP1 and GRP78.In summary,the upregulation of RACK1 following brain contusion exerted neuroprotective effects against secondary brain injury,which were probably mediated by activation of the IRE1-XBP1 pathway.更多还原