Department of Chemical Processes and Environments, Faculty of Environmental Engineering, The University of Kitakyushu, Kitakyushu, Fukuoka, 808-0135, Japan.
Free Radic Res. 2011 May;45(5):527-33. doi: 10.3109/10715762.2011.555481. Epub 2011 Feb 4.
To evaluate the defence capacities of embryonic stem (ES) cells against gene impairment, this study measured the levels of 8-hydroxyguanine (8-OH-Gua), a well-known marker of oxidative stress in DNA, and its repair capacity during differentiation. Undifferentiated ES cells (EB3) were cultured without leukaemia inhibitory factor (LIF) for 0, 4 and 7 days and are referred to as ES-D0, ES-D4 and ES-D7, respectively. These three cell lines were treated with 300 μM hydrogen peroxide (H(2)O(2)) for 48 and 72 h. After treatment, the amounts of 8-OH-Gua in the cells were determined by the high-performance liquid chromatography (HPLC)-electrochemical detector (ECD) method. The levels of 8-OH-Gua in ES-D7 treated with H(2)O(2) were higher than those in ES-D0 and ES-D4, suggesting that the DNA in the undifferentiated cells was protected against gene impairment, as compared to that in the differentiated cells. To examine the repair capacity for 8-OH-Gua, this study analysed the expression of 8-OH-Gua repair-associated genes, 8-oxoguanine DNA glycosylase 1 (OGG1), MutY homolog (MUTYH) and Mut T homolog 1 (MTH1), in ES-D0, ES-D4 and ES-D7. The mRNA levels of MUTYH and MTH1 showed no significant change, whereas OGG1 mRNA was significantly decreased in ES-D7 treated with H(2)O(2). Moreover, it was observed that ES-D7 treated with H(2)O(2) readily underwent apoptosis, in comparison to its undifferentiated counterparts, ES-D0 and ES-D4. Taken together, ES cells are more resistant to DNA oxidative stresses than differentiated cells.
为了评估胚胎干细胞（ES 细胞）对基因损伤的防御能力，本研究测量了 DNA 中氧化应激的标志物 8-羟基鸟嘌呤（8-OH-Gua）及其在分化过程中的修复能力。未分化的 ES 细胞（EB3）在没有白血病抑制因子（LIF）的情况下培养 0、4 和 7 天，分别称为 ES-D0、ES-D4 和 ES-D7。这三种细胞系用 300 μM 过氧化氢（H 2 O 2 ）处理 48 和 72 小时。处理后，通过高效液相色谱（HPLC）-电化学检测器（ECD）法测定细胞中 8-OH-Gua 的含量。用 H 2 O 2 处理的 ES-D7 中的 8-OH-Gua 水平高于 ES-D0 和 ES-D4，这表明与分化细胞相比，未分化细胞的 DNA 受到基因损伤的保护。为了检测 8-OH-Gua 的修复能力，本研究分析了 8-OH-Gua 修复相关基因 8-氧鸟嘌呤 DNA 糖基化酶 1（OGG1）、MutY 同源物（MUTYH）和 Mut T 同源物 1（MTH1）在 ES-D0、ES-D4 和 ES-D7 中的表达。MUTYH 和 MTH1 的 mRNA 水平没有明显变化，而用 H 2 O 2 处理的 ES-D7 中的 OGG1 mRNA 显著下降。此外，与未分化的 ES-D0 和 ES-D4 相比，用 H 2 O 2 处理的 ES-D7 更容易发生凋亡。总之，ES 细胞比分化细胞更能抵抗 DNA 氧化应激。
