活性氧介导醛固酮诱导的足细胞凋亡

Role of reactive oxygen species in podocytes apoptosis induced by aldosterone

目的 观察醛固酮（ALD）及其受体拮抗剂螺内酯（SPI）对足细胞活性氧（ROS）产生及凋亡的影响,并探讨其可能机制.方法 体外培养条件的永生化小鼠足细胞系,分为空白对照组、ALD组、SPI组、ALD＋SPI组;用荧光分光光度计检测足细胞内ROS水平;间接免疫荧光检测nephrin表达;流式细胞仪检测足细胞凋亡率;RT-PCR、Western印迹法检测bax、bcl-2 mRNA及蛋白表达.同时观察抗氧化剂N-乙酰半胱氨酸（NAC）对上述效应的阻断作用.结果 与对照组相比,ALD诱导足细胞ROS产生增多（P＜0.05）,该作用可被SPI阻断（P＜0.05）.ALD可诱导足细胞nephrin表达降低及足细胞凋亡（P＜0.05）,同时伴有bax mRNA、蛋白表达升高及bcl-2 mRNA、蛋白表达降低（P＜0.05）,SPI及NAC可阻断这一变化（P＜0.05）.结论 ALD通过ROS途径作用于盐皮质激素受体上调促凋亡因子bax表达,下调抑凋亡因子bcl-2表达,进而诱导足细胞凋亡.

Objective To access the effects of aldosterone （ALD） and its receptor antagonist- spironolactone （SPI） on the production of reactive oxygen species （ROS） and apoptosis in podocytes and to explore the possible mechanism involved. Methods Conditionally immortalized mouse podocytes were divided into control group, ALD group, SPI group and SPI ＋ALD group. The level of ROS production and the expression of nephrin protein were assayed by fluorescent spectrophotometry and indirect immunofluorescence technology. The apoptosis rate of podocytes was monitored by flow cytometry. The expression of bax and bcl-2 mRNA and protein was detected by RT-PCR and Western blotting methods. The anti-oxidant N-acetylcysteine （NAC）was applied to determine whether the effects of ALD on podocytes were mediated by ROS pathway.Results Compared with the control group, ALD significantly increased ROS production in podocytes （P〈0.05）. SPI completely abolished the above-mentioned effect of ALD （P〈0.05）. ALD induced the down-regulation of the expression of nephrin and the up-regulation of podocytes apoptosis （P〈0.05）, which was accompanied with the elevated expression of bax mRNA and protein and the reduced expression of bcl-2 mRNA and protein （P〈0.05）. SPI or NAC prevented the above-mentioned changes induced by ALD （P〈0.05）. Conclusion ALD increases theexpression of pro-apoptotic factor （bax） but decreases the expression of anti-apoptotic factor （bcl-2）to induce podocytes apoptosis through the mineralocorticoid receptor （MR） possibly via the mechanisms involving ROS pathway.