摘要目的:探讨核因子E2相关因子2（Nrf2）在镧活化基质金属蛋白酶9（MMP9）致脉络丛上皮细胞紧密连接蛋白表达改变中的作用研究。方法:于2020年10月，采用永生化大鼠脉络丛上皮细胞（Z310细胞）体外模拟血脑脊液屏障，分为对照组和0.125、0.25、0.5 mmol/L氯化镧处理组。不同浓度氯化镧处理Z310细胞24 h后，倒置显微镜观察细胞形态学变化，细胞免疫荧光法观察MMP9、闭合蛋白（occludin）和胞质附着蛋白1（ZO-1）蛋白表达水平，蛋白免疫印迹法检测MMP9、组织金属蛋白酶抑制剂1（TIMP1）、occludin、ZO-1和Nrf2蛋白表达水平，流式细胞仪检测细胞内活性氧（ROS）水平。结果:与对照组比较，氯化镧处理组Z310细胞体积变小，细胞间连接变少，死亡细胞、细胞碎片逐渐增多。0.25、0.5 mmol/L氯化镧处理组细胞内MMP9蛋白表达水平明显高于对照组（ P<0.05），且TIMP1及紧密连接蛋白occludin、ZO-1蛋白表达水平较对照组明显降低（ P<0.05）；而与对照组比较，0.25、0.5 mmol/L氯化镧处理组细胞内ROS产生水平明显增加（ P<0.05），0.125、0.25、0.5 mmol/L氯化镧处理组细胞内Nrf2蛋白表达水平明显下降（ P<0.05）。 结论:镧可能通过下调Nrf2表达造成细胞内ROS水平增加，从而活化MMP9致细胞间紧密连接蛋白occludin、ZO-1表达水平下降。

abstractsObjective:To investigate the effect of nuclear factor erythroid 2-related factor 2 (Nrf2) in the alteration of tight junction protein expression in choroid plexus epithelial cells created by lanthanum-activated matrix metalloproteinase 9 (MMP9) .Methods:In October 2020, immortalized rat choroid plexus epithelial cell line (Z310) cells were used as the blood-cerebrospinal fluid barrier in vitro, and were divided into control group and 0.125, 0.25, 0.5 mmol/L lanthanum chloride (LaCl 3) treatment group. After treating Z310 cells with different concentrations of LaCl 3 for 24 hours, the morphological changes of Z310 cells were observed under inverted microscope, the protein expression levels of MMP9, occludin and zonula occludens-1 (ZO-1) were observed by cellular immunofluorescence method, and the protein expression levels of MMP9, tissue inhibitors of metalloproteinase1 (TIMP1) , occludin, ZO-1 and Nrf2 were detected by Western blotting. The level of reactive oxygen species (ROS) in cells was detected by flow cytometry. Results:Compared with the control group, Z310 cells in the LaCl 3 treatment group were smaller in size, with fewer intercellular junctions, and more dead cells and cell fragments. The expression level of MMP9 protein in cells treated with 0.25 and 0.5 mmol/L LaCl 3 was significantly higher than that in the control group ( P<0.05) , and the expression level of TIMP1 and tight junction proteins occudin and ZO-1 was significantly lower than that in the control group ( P<0.05) . Compared with the control group, the ROS production level in the 0.25, 0.5 mmol/L LaCl 3 treatment group was significantly increased ( P<0.05) , and the Nrf2 protein expression level in the 0.125, 0.25, 0.5 mmol/L LaCl 3 treatment group was significantly decreased ( P<0.05) . Conclusion:Lanthanum may increase the level of ROS in cells by down regulating the expression of Nrf2, thus activating MMP9 to reduce the expression level of intercellular tight junction proteins occludin and ZO-1.