Reporter gene mutation in the livers of <i>gpt</i> delta mice treated with 5-(hydroxymethyl)-2-furfural, a contaminant of various foods

Abstract

-A major product formed during the Maillard reaction is 5-(hydroxymethyl)-2-furfural (HMF), which is present in various foods and beverages such as honey and fruit juice. HMF was shown to be a hepatocarcinogen in female mice using long-term bioassays. Although HMF is not a mutagen in conventional in vitro mutation assays, 5-sulfoxymethylfurfural (SMF), a reactive metabolite of HMF produced following sulfotransferase conjugation, does show mutagenicity. Thus, HMF-induced hepatocarcinogenesis likely involves genotoxic mechanisms. To clarify the mechanisms underlying HMF-induced hepatocarcinogenesis, female B6C3F 1 gpt delta mice were given HMF at carcinogenic doses (188 or 375 mg/kg b.w.) by gavage for 5 days per week for 4 weeks. This treatment produced no significant differences in mutant frequencies (MFs) of gpt and red/gam (Spi -) genes among the groups. These results suggest that genotoxicity does not contribute to HMF-induced hepatocarcinogenesis. Parameters related to cell proliferation, such as proliferation cell nuclear antigen-labeling index and Cyclin D1 and E1 mRNA expression, exhibited no significant changes in the livers of HMF-treated groups. In view of the lack of carcinogenicity in rats, HMF may be considered to be a weak carcinogen. These results help us to understand the underlying mechanisms of action of HMF carcinogenesis.Key words: 5-(hydroxymethyl)-2-furfural, 5-sulfoxymethylfurfural, gpt delta mice, in vivo mutagenicity Correspondence: Takashi Umemura (E-mail: umemura@nihs.go.jp) LetterThe Journal of Toxicological Sciences (J. Toxicol. Sci.) Vol.37, No.5, 1077-1082, 2012 1077 T1A1 (Glatt et al., 2005T1A1 (Glatt et al., , 2012. The presence of SMF in the serum of mice to which HMF was administered intravenously (Monien et al., 2009), strongly supports the involvement of SMF in HMF-induced hepatocarcinogenesis.Reporter gene mutation assays are useful tools for investigating in vivo mutagenicity of environmental agents (WHO, 2006). The remarkable advantage of these assays is that the absorption, distribution, metabolism and excretion of test chemicals can be taken into account (Nohmi et al., 2000). In the present study, we performed an in vivo mutation assay with HMF using B6C3F 1 gpt delta female mice and the same conditions as the long-term bioassay, along with measurements of the proliferation cell nuclear antigen (PCNA) labeling index of hepatocytes and mRNA expression levels of several cell cycle-related genes. MATERIALS AND METHODS Experimental animals and housing conditionsThe protocol for this study was approved by the Animal Care and Utilization Committee of the National Institute of Health Sciences. Female B6C3F 1 gpt delta mice carrying 80 tandem copies of the transgene lambda EG10 in haploid genome were raised by mating C57BL/6 gpt delta and non-transgenic C3H/He mice (Japan SLC, Inc., Shizuoka, Japan). 15 female B6C3F 1 gpt delta mice were each randomized by weight into three groups. The mice were housed in a room with a barrier system and maintained under constant tempe...

Assessing the effect of 5‐hydroxymethylfurfural on selected components of immune responses in mice immunised with ovalbumin

“…Similar to these results, Matsushita et al reported that the final body weight (BW) of mice in a group treated with 5-HMF (188 mg kg −1 BW) was significantly increased. 54 In opposition to this, a National Toxicology Program study indicated that the body weight gain of male mice (1500 mg kg −1 BW) were significantly lower than in the sensitised group. 23 In contrast to most of the previous studies, we administered 5-HMF through pellet diets, instead of gavage, which could affect the results of food intake and therefore body weight.…”

“…Similar to these results, Matsushita et al . reported that the final body weight (BW) of mice in a group treated with 5‐HMF (188 mg kg −1 BW) was significantly increased . In opposition to this, a National Toxicology Program study indicated that the body weight gain of male mice (1500 mg kg −1 BW) were significantly lower than in the sensitised group .…”