Protective Effect of Maize Silks (Maydis stigma) Ethanol Extract on Radiation-Induced Oxidative Stress in Mice

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.