Nitroxide TEMPO: A genotoxic and oxidative stress inducer in cultured cells

作者：Guo Xiaoqing; Mittelstaedt Roberta A; Guo Lei; Shaddock Joseph G; Heflich Robert H; Bigger Anita H; Moore Martha M; Mei Nan^*

来源：Toxicology in Vitro, 2013, 27(5): 1496-1502.

DOI：10.1016/j.tiv.2013.02.019

• Nitroxide
• Mouse lymphoma assay
• Micronucleus assay
• Loss of heterozygosity
• Glutathione
• Oxidative stress

2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) is a low molecular weight nitroxide and stable free radical. In this study, we investigated the cytotoxicity and genotoxicity of TEMPO in mammalian cells using the mouse lymphoma assay (MLA) and in vitro micronucleus assay. In the absence of metabolic activation (S9), 3 mM TEMPO produced significant cytotoxicity and marginal mutagenicity in the MLA; in the presence of 59, treatment of mouse lymphoma cells with 1-2 mM TEMPO resulted in dose-dependent decreases of the relative total growth and increases in mutant frequency. Treatment of TK6 human lymphoblastoid cells with 0.9-23 mM TEMPO increased the frequency of both micronuclei (a marker for clastogenicity) and hypodiploid nuclei (a marker of aneugenicity) in a dose-dependent manner; greater responses were produced in the presence of S9. Within the dose range tested, TEMPO induced reactive oxygen species and decreased glutathione levels in mouse lymphoma cells. In addition, the majority of TEMPO-induced mutants had loss of heterozygosity at the Tk locus, with allele loss of <= 34 Mbp. These results indicate that TEMPO is mutagenic in the MLA and induces micronuclei and hypodiploid nuclei in TK6 cells. Oxidative stress may account for part of the genotoxicity induced by TEMPO in both cell lines. Published by Elsevier Ltd.

• 出版日期2013-8