β-lapachone (β-lap) is reduced in tumor cells by the enzyme NAD(P)H: quinone acceptor oxidoreductase 1 (NQO1) to a labile hydroquinone which spontaneously reoxidises to β-lap, thereby generating reactive oxygen species (ROS) and oxidative stress. To test for the consequences of an acute exposure of brain cells to β-lap, cultured primary rat astrocytes were incubated with β-lap for up to 4 h. The presence of β-lap in concentrations of up to 10 µM had no detectable adverse consequences, while higher concentrations of β-lap compromised the cell viability and the metabolism of astrocytes in a concentration- and time-dependent manner with half-maximal effects observed for around 15 µM β-lap after a 4 h incubation. Exposure of astrocytes to β-lap caused already within 5 min a severe increase in the cellular production of ROS as well as a rapid oxidation of glutathione (GSH) to glutathione disulfide (GSSG). The transient cellular accumulation of GSSG was followed by GSSG export. The β-lap-induced ROS production and GSSG accumulation were completely prevented in the presence of the NQO1 inhibitor dicoumarol. In addition, application of dicoumarol to β-lap-exposed astrocytes caused rapid regeneration of the normal high cellular GSH to GSSG ratio. These results demonstrate that application of β-lap to cultured astrocytes causes acute oxidative stress that depends on the activity of NQO1. The sequential application of β-lap and dicoumarol to rapidly induce and terminate oxidative stress, respectively, is a suitable experimental paradigm to study consequences of a defined period of acute oxidative stress in NQO1-expressing cells.

中文翻译：

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β-Lapachone 在大鼠原代星形胶质细胞培养物中诱导急性氧化应激，其由 NQO1 抑制剂双香豆素终止。

β-lapachone (β-lap) 在肿瘤细胞中被 NAD(P)H: 醌受体氧化还原酶 1 (NQO1) 酶还原为不稳定的氢醌，后者会自发地再氧化为 β-lap，从而产生活性氧 (ROS) 和氧化应激。为了测试脑细胞急性暴露于 β-lap 的后果，培养的原代大鼠星形胶质细胞与 β-lap 孵育长达 4 小时。浓度高达 10 µM 的 β-lap 的存在没有可检测到的不良后果，而较高浓度的 β-lap 以浓度和时间依赖性方式损害细胞活力和星形胶质细胞的代谢，观察到一半最大效应孵育 4 小时后，大约 15 μM β-lap。星形胶质细胞暴露于 β-lap 已在 5 分钟内导致细胞产生 ROS 的严重增加以及谷胱甘肽 (GSH) 快速氧化为二硫化谷胱甘肽 (GSSG)。GSSG 的瞬时细胞积累之后是 GSSG 输出。在 NQO1 抑制剂双香豆素的存在下，完全阻止了 β-lap 诱导的 ROS 产生和 GSSG 积累。此外，将双香豆素应用于暴露于 β-lap 的星形胶质细胞会导致正常高细胞 GSH 与 GSSG 比率的快速再生。这些结果表明，将 β-lap 应用于培养的星形胶质细胞会导致急性氧化应激，这取决于 NQO1 的活性。依次应用 β-lap 和双香豆素分别快速诱导和终止氧化应激，