The potentiating and protective effects of ascorbate on oxidative stress depend upon the concentration of dietary iron fed C3H mice.
The potentiating and protective effects of ascorbate on oxidative stress depend upon the concentration of dietary iron fed C3H mice.
复制标题
抗坏血酸对氧化应激的增强和保护作用取决于膳食铁喂养的 C3H 小鼠的浓度。
DOI：
10.1016/j.jnutbio.2006.05.004
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Bowlus,ChristopherL
中科院分区：
文献类型：
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作者：
Premkumar,Kumpati;Min,Kyungmi;Alkan,Zeynep;Hawkes,WayneC;Ebeler,Susan;Bowlus,ChristopherL
抗坏血酸(AA)是一种抗氧化剂，在铁和过氧化氢存在的情况下，它会在体外增加羟基自由基的产生。AA在体内是否具有类似的促氧化剂特性，可能取决于铁和AA浓度的相对平衡。在本研究中，C3H小鼠饲喂添加100或300 mg/kg铁的饲料，添加或不添加AA(15g/kg)，为期12个月。低铁或高铁饲料中添加AA的小鼠肝脏AA浓度较高(P=0.0001)，而无论补充AA与否，高铁饮食与显著降低肝脏AA浓度相关(P=0.0001)。只有喂食高铁饲料和AA的小鼠的肝铁浓度显著更高(P=0.05)。在高铁组，AA降低了氧化应激，表现为更高的谷胱甘肽过氧化物酶、超氧化物歧化酶和过氧化氢酶活性，以及显著降低的4-羟基烯醛(HAE)和丙二醛(MDA)浓度。在喂食低铁饮食的小鼠中，AA与较高的HAE和MDA浓度以及较低的SOD活性有关。然而，AA不会增加低铁饮食中修饰DNA碱基的浓度，但与高铁饮食喂养的小鼠的修饰DNA碱基浓度显著降低有关。综上所述，膳食AA在低铁浓度下表现出温和的促氧化作用，但对膳食铁诱导的小鼠肝脏氧化应激和DNA损伤有很强的抗氧化作用。
Ascorbic acid (AA) is an antioxidant that, in the presence of iron and hydrogen peroxide, increases the production of hydroxyl radicals in vitro. Whether AA has similar pro-oxidant properties in vivo may depend upon the relative balance of iron and AA concentrations. In this study, C3H mice were fed diets supplemented with 100 or 300 mg/kg iron, with or without AA (15 g/kg), for 12 months. Liver AA concentrations were greater in mice fed AA-supplemented diets with either low or high iron (P=.0001), while the high-iron diet was associated with a significantly lower liver AA concentration regardless of AA supplementation (P=.0001). Only mice fed the high-iron diet with AA had a significantly greater liver iron concentration (P=.05). In the high-iron group, AA reduced oxidative stress, as measured by greater activities of glutathione peroxidase, superoxide dismutase (SOD) and catalase and by significantly lower concentrations of 4-hydroxylalkenal (HAE) and malondialdehyde (MDA). In mice fed the low-iron diet, AA was associated with greater concentrations of HAE and MDA and with lower activities of SOD. However, AA did not increase the concentrations of modified DNA bases with the low-iron diet but was associated with significantly lower concentrations of modified DNA bases in mice fed the high-iron diet. In conclusion, dietary AA appears to have mild pro-oxidant properties at low-iron concentrations but has a strong antioxidant effect against oxidative stress and DNA damage induced by dietary iron in mouse liver.