模拟微重力对大鼠嗜铬细胞瘤细胞蛋白酪氨酸硝基化的影响

目的研究微重力状态下活性氮自由基（RNS）对神经细胞蛋白质氧化修饰的影响。方法以大鼠嗜铬细胞瘤（PCI2）细胞作为神经细胞模型，利用水平轴回转器模拟微重力效应。回转72h后，对回转和对照组细胞进行一氧化氮合酶和硝基酪氨酸的免疫细胞化学染色分析，同时采用硝酸盐还原酶偶联法测定回转PC12细胞的一氧化氮（NO）水平，竞争性ELISA方法定量检测细胞硝基酪氨酸的水平。结果回转后PC12细胞诱导型一氧化氮合酶（iNOS）和硝基酪氨酸免疫细胞化学染色均增强。回转后PCI2细胞NO水平升高（P〈0．01），蛋白质酪氨酸硝基化程度显著增加（P〈0．01）。结论模拟失重可诱导PC12细胞NO的合成，增加蛋白质氧化损伤程度。

Effect of simulated microgravity on protein nitration in pheochromocytoma (PC12) cells of rats

Objective To investigate the effects of reactive nitrogen species(RNS) on protein modification of PC12 cells in simulated microgravity.Methods A ground based research was(undertaken) using a clinostat to simulate microgravity,and rat pheochromocytoma(PC12) cells used as neuronal cell model.After PC12 cells were cultured in simulated weightlessness condition for 72 h,the protein expressions of nitric oxide synthase(iNOS) and nitrotyrosine were examined by(immunocytochemical analysis,) and levels of nitric oxide(NO) and nitrotyrosine were determined by nitrate reductase coupling method and competitive ELISA respectively.Results As compared with PC12 cells cultured in standstill condition,the immunocytochemical staining of iNOS and(nitrotyrosine was) enhanced,and the levels of NO and nitrotyrosine were significantly increased in(cells cultured in the simulated) microgravity condition(P<0.01).Conclusions Simulated weightlessness may induce the(over) production of NO,and resulted in increased protein oxidative damage in PC12 cells.