National Center for Natural Product Research, School of Pharmacy, University of Mississippi, MS 38677, USA.
Comp Biochem Physiol C Toxicol Pharmacol. 2011 Jan;153(1):159-67. doi: 10.1016/j.cbpc.2010.10.002. Epub 2010 Oct 18.
Although the mechanism of ethanol toxicity during embryogenesis is unknown, our earlier studies on Japanese rice fish (Oryzias latipes) embryos indicated that the effects might be mediated through oxidative stress. In this study we have determined the oxidative stress and the mRNA content of four antioxidant enzymes (catalase, glutathione reductase, glutathione-S-transferase, and superoxide dismutase) during Japanese rice fish embryogenesis (from 0 day post-fertilization to hatching) and after exposing the embryos to ethanol (100 and 300 mM) for 48 h at three stages (0-2, 1-3 and 4-6 days post-fertilization, dpf) of organogenesis. We observed that oxidative stress was minimal in blastula, gastrula or neurula stages, increased gradually with the advancement of morphogenesis and reached its maximum level in hatchlings. The antioxidant enzyme mRNAs were constitutively expressed throughout development; however, the expression pattern was not identical among the enzymes. Catalase and superoxide dismutase (SOD) mRNAs were minimal in the fertilized eggs, but increased significantly in 1 dpf and then either sharply dropped (SOD) or maintained a steady-state (catalase). Glutathione-S-transferase (GST) was very high in fertilized eggs and sharply dropped 1 dpf and then gradually increased thereafter. Glutathione reductase (GR) maintained a steady-state throughout the development. Ethanol was able to attenuate oxidative stress in embryos exposed only to 300 mM 1-3 dpf; no significant difference with controls was observed in other ethanol-treated groups. The antioxidant enzyme mRNAs also remained unaltered after ethanol treatment. From these data we conclude that the attenuation of oxidative stress by ethanol is probably due to the inhibition of normal growth of the embryos rather than by inhibiting catalase, GST, GR or SOD-dependent activities.
虽然乙醇在胚胎发生期间的毒性机制尚不清楚，但我们之前对日本稻鱼（Oryzias latipes）胚胎的研究表明，其影响可能是通过氧化应激介导的。在这项研究中，我们测定了日本稻鱼胚胎发生期间（从受精后 0 天到孵化）和暴露于乙醇（100 和 300mM）48 小时后（在器官发生的三个阶段：受精后 0-2 天、1-3 天和 4-6 天）的氧化应激和四种抗氧化酶（过氧化氢酶、谷胱甘肽还原酶、谷胱甘肽-S-转移酶和超氧化物歧化酶）的 mRNA 含量。我们观察到，在囊胚、原肠胚或神经胚阶段氧化应激最小，随着形态发生的进展逐渐增加，并在孵化时达到最大值。抗氧化酶 mRNA 在整个发育过程中持续表达；然而，酶之间的表达模式并不相同。过氧化氢酶和超氧化物歧化酶（SOD）mRNA 在受精卵中含量最低，但在 1 天明显增加，然后急剧下降（SOD）或保持稳定状态（过氧化氢酶）。谷胱甘肽-S-转移酶（GST）在受精卵中含量很高，在 1 天急剧下降，然后逐渐增加。谷胱甘肽还原酶（GR）在整个发育过程中保持稳定。仅在 1-3 天暴露于 300mM 乙醇的胚胎中，乙醇能够减轻氧化应激；与对照组相比，其他乙醇处理组没有观察到显著差异。乙醇处理后，抗氧化酶 mRNA 也保持不变。从这些数据中我们得出结论，乙醇对氧化应激的抑制可能是由于抑制胚胎的正常生长，而不是通过抑制过氧化氢酶、GST、GR 或 SOD 依赖性活性。
