Department of Toxicology, Faculty of Preventive Medicine, Fourth Military Medical University, Xi'an 710032, Shanxi, People's Republic of China.
Plant Foods Hum Nutr. 2010 Sep;65(3):271-6. doi: 10.1007/s11130-010-0172-6.
Maize silks, dried cut stigmata of maize female flowers, are a traditional medicinal plant. This study was conducted to investigate the antioxidant effect of maize silks ethanol extract (MSE) against oxidative damage in vivo. γ-radiation was employed to induce oxidative stress in mice and the variation of malondialdehyde (MDA), glutathione/glutathione disulfide ratio (GSH/GSSG), blood cells, NF-E2-related factor 2 (Nrf2) and related antioxidant enzymes were examined. The results showed that radiation elevate levels of MDA, induce hematological abnormalities and decrease levels of GSH/GSSG and Nrf2 expression in liver and kidney. MSE administration significantly abolished elevation of MDA levels in liver, maintained hepatic GSH/GSSG ratio and ameliorated hematological abnormalities dose dependently. Moreover, MSE up-regulated the hepatic protein expression of Nrf2 dose dependently and the activities as well as protein expression of Nrf2-related antioxidant enzymes were also increased. However, the antioxidant ability of MSE seemed not to be as effective in kidney as in liver. These findings firstly proved the protective role of MSE against oxidative stress, which was in part via up-regulation of Nrf2 and seemed to be tissue specific.
玉米须，即玉米雌花的干燥柱头，是一种传统的药用植物。本研究旨在探讨玉米须乙醇提取物（MSE）对体内氧化损伤的抗氧化作用。采用γ射线诱导小鼠产生氧化应激，检测丙二醛（MDA）、谷胱甘肽/谷胱甘肽二硫化物比（GSH/GSSG）、血细胞、核因子 E2 相关因子 2（Nrf2）和相关抗氧化酶的变化。结果表明，辐射会升高 MDA 水平，导致血液异常，并降低肝、肾组织中 GSH/GSSG 比值和 Nrf2 的表达。MSE 给药可显著抑制 MDA 水平的升高，剂量依赖性地维持肝 GSH/GSSG 比值，改善血液异常。此外，MSE 可剂量依赖性地上调 Nrf2 的肝蛋白表达，以及 Nrf2 相关抗氧化酶的活性和蛋白表达。然而，MSE 的抗氧化能力在肾脏似乎不如在肝脏有效。这些发现首次证明了 MSE 对氧化应激的保护作用，部分是通过上调 Nrf2 实现的，且似乎具有组织特异性。
