Disruption of redox homeostasis and carcinogen metabolizing enzymes changes by administration of vitamin E to rats

被引:17
作者
Vivarelli, Fabio [1 ]
Canistro, Donatella [1 ]
Franchi, Paola [2 ]
Sapone, Andrea [1 ]
Vornoli, Andrea [3 ]
Della Croce, Clara [4 ]
Longo, Vincenzo [4 ]
Lucarini, Marco [2 ]
Paolini, Moreno [1 ]
机构
[1] Univ Bologna, Mol & Toxicol Unit, Dept Pharm & Biotechnol, Alma Mater Studiorum, Via Irnerio 48, I-40126 Bologna, Italy
[2] Univ Bologna, Dept Chem G Ciamician, Alma Mater Studiorum, Via Selmi 2, I-40126 Bologna, Italy
[3] CNR, Inst Clin Physiol, Via Moruzzi 1, I-56124 Pisa, Italy
[4] CNR, Inst Agr Biol & Biotechnol, Via Moruzzi 1, I-56124 Pisa, Italy
关键词
Vitamin E; Cytochrome P450; Phase II enzymes; Antioxidant enzymes; Free radical species; Chemopreventive agent; RANDOMIZED CONTROLLED-TRIAL; RADICAL-PROBE TECHNIQUE; OXIDATIVE STRESS; CARDIOVASCULAR-DISEASE; BETA-CAROTENE; ALPHA-TOCOPHEROL; ANTIOXIDANT PARADOX; E SUPPLEMENTATION; CANCER INCIDENCE; SENSITIVE ASSAY;
D O I
10.1016/j.lfs.2015.12.033
中图分类号
R-3 [医学研究方法]; R3 [基础医学];
学科分类号
1001 ;
摘要
Aims: A large meta-analysis of randomized clinical trials has seriously questioned chemoprevention based on vitamins including vitamin E (VE), and an increased risk for cancer among long-term users was actually seen. However, the mechanism underlying these findings still remain unknown. To clarify the mechanism, in an in vivo model we studied the putative disruption of redox homeostasis and the perturbation of carcinogen metabolizing enzymes determined by VE. Main methods: Male Sprague-Dawley rats were treated ip with either 100 or 200 mg/kg b.w. daily for 7 or 14 consecutive days. Controls received vehicle only. Cytochrome P450 (CYP) content, CYP-reductase, CYP-linked monooxygenases, as well as phase-II and the antioxidant enzymes catalase and NAD(P)H: quinone reductase were investigated in both liver and kidney. Free radical species in tissue subcellular preparations were measured by electronic paramagnetic resonance (EPR) spectroscopy coupled to a radical probe technique. Key findings: No substantial changes of hepatic xenobiotic metabolism enzymes were determined by VE. Conversely, a powerful booster effect of various renal phase-I carcinogen bioactivating enzymes at both dosages and observational times was recorded. While no relevant changes of post-oxidative phase-II reactions were found in the liver, a significant inactivating effect was caused by VE in renal tissues. Antioxidant enzymes were found mainly downregulated by the treatment. In the kidney, a marked free radical over-generation linked to CYP induction was observed. Significance: This study proved that VE acts as a co-carcinogen and pro-oxidant agent. Such epigenetic mechanisms may contribute to explain the harmful outcomes observed in humans. (C) 2015 Elsevier Inc. All rights reserved.
引用
收藏
页码:166 / 173
页数:8
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