二氮嗪拮抗Aβ_(1-42)致胆碱能神经元氧化应激的机制研究

PROTECTIVE EFFECT OF DIAZOXIDE ON OXIDATIVE STRESS INDUCED BY AΒ_(1-42) IN CHOLINERGIC NEURONS

目的探索二氮嗪拮抗β-淀粉样蛋白(Aβ_(1-42))致原代培养胆碱能神经元氧化应激的机制。方法采用Aβ_(1-42)对原代培养大鼠胆碱能神经元进行干预,建立阿尔茨海默病(AD)细胞凋亡模型;采用二氮嗪(预处理1h)对其干预,Aβ_(1-42)作用72h后采用噻唑蓝(MTT)比色法检测细胞存活率,Western blot法检测NADPH氧化酶亚基gp91phox及p47phox蛋白表达水平的变化,DCFHDA荧光检测细胞内ROS含量。结果与对照组相比,Aβ_(1-42)组细胞活性显著降低(P<0.01),NADPH氧化酶亚基gp91phox及p47phox蛋白表达显著增多(P<0.05),ROS水平显著升高(P<0.05);二氮嗪预处理组与对照组比较细胞活性明显下降(P<0.05),ROS水平升高,但与Aβ_(1-42)组比较细胞活性显著改善(P<0.01),gp91phox及p47phox蛋白表达明显降低(P<0.05),ROS水平显著下降(P<0.05)。结论二氮嗪预处理可降低NADPH氧化酶活性亚基的表达,从而减少ROS的产生,具有拮抗Aβ_(1-42)致胆碱能神经元氧化应激的作用。

Objective To explore the mechanism of using diazoxide to inhibit oxidative stress induced by Aβl-42in Cholinergic neurons. Methods Primary cultured rat cholinergic neurons were treated with Aβ1-42 to establish cell model of Alzheimer＇s disease （AD）. Cholinergic neurons were treated with diazoxide （after one hour of pretreatment） , Aβ1-42was used for 72h to detect cell viability by MTT colorimetry, the expres- sions of NADPH oxidase subunit p47phox and the gp91phox were measured by Western blot and levels of ROS in cells were dectected by DCFH-DA fluorescence. Results Compared with the control group, the cell activity of Aβ1-42group was significantly decreased（ P 〈0.01）, the expression of gp91phox and p47phox was significantly increased（ P 〈0.05）, the ROS levels were significantly increased （ P 〈0.05）. The cell activity in diazoxide preconditioning group was significantly reduced （ P 〈0.05）, however, when com- pared with the Aβ1-42group, the cell activity of diazoxide preconditioning group improved significantly （ P 〈0.01）, the gp91phox and p47phox protein expression and ROS levels were significantly decreased （ P 〈0.05）. Conclusion Diazoxide preconditioning can reduce the expression of NADPH oxidase subunits, there- by decrease the generation of ROS and extenuate oxidative stress induced by Aβ1-42 in cholinergic neurons.