脑缺血急性期神经元上P-糖蛋白的过表达调控机制的研究

Study on the regulation mechanism of P-glycoprotein overexpression in neurons during acute cerebral ischemia

目的探究脑缺血急性期P-糖蛋白(P-gp)在半影区神经元的表达变化,进而分析P-gp的调控因素及干预靶点。方法构建大脑中动脉闭塞(MCAO)模型,把MCAO后1、2、3、4、5和6 h的大鼠分为1、2、3、4、5和6 h缺血组,假手术组仅暴露右侧颈总动脉、颈外动脉和颈内动脉,不闭塞血管。检测P-gp在神经元上的表达变化、检测活性氧(ROS)含量、检测核因子-κB(NF-κB)的表达和定位、检测炎症因子含量。培养原代神经元以验证ROS或炎症因子对P-gp表达的影响。结果体内实验结果显示,假手术组和1、2、3、4、5和6 h缺血组的梗死体积分别为0、(2.08±1.91)%、(4.92±3.36)%、(6.02±3.91)%、(14.77±5.63)%、(15.43±6.58)%和(22.63±7.13)%;各组脑组织ROS表达水平分别为1、1.61±0.08、1.18±0.08、1.50±0.04、1.41±0.11、1.92±0.04、2.20±0.17;P-gp在缺血4 h时在神经元中的表达显著上调,共定位比例高达(78.62±12.41)%,以上指标,缺血组与假手术组比较,差异均有统计学意义(均P<0.05)。结论脑缺血急性期ROS通过激活炎症反应、在特定时区上调神经元中P-gp的表达。

Objective To explore the expression change of P-glycoprotein(P-gp)in penumbra neurons during acute cerebral ischemia,and then to analyze the regulatory factors and intervention targets of P-gp.Methods The middle cerebral artery occlusion(MCAO)model was constructed.The rats at 1,2,3,4,5 and 6 h after MCAO were divided into 1,2,3,4,5 and 6 h ischemia groups.The sham operation group only exposed the right common carotid artery,external carotid artery and internal carotid artery without blocking the blood vessels.The neurological deficit and infarct rate after MCAO were observed;the expression of P-gp in neurons,the content of reactive oxygen species(ROS),the expression and localization of nuclear factor-k B(NF-kB),as well as tissue content of inflammatory factor were detected O-6 h after MCAO.Primary neurons were cultured to verify the effect of ROS or inflammatory factors on P-gp expression.Results The results of in vivo experiments showed that the infarct volume of sham operation group,1,2,3,4,5 and 6 h ischemia group were 0,(2.08±1.91)%,(4.92±3.36)%,(6.02±3.91)%,(14.77±5.63)%,(15.43±6.58)%,(22.63±7.13)%,respectively;the expression levels of ROS in brain tissue of each group were 1,1.61±0.08,1.18±0.08,1.50±0.04,1.41±0.11,1.92±0.04,2.20±0.17,respectively.The expression of P-gp in neurons was up-regulated at 4 h after ischemia,and the co-localization ratio was as high as(78.62±12.41)%;there were significant differences in the above indexes between the ischemic group and the sham operation group(all P<0.05).Conclusion ROS can up regulate the expression of P-gp in neurons in specific time zone by activating inflammatory response in acute cerebral ischemia.