Combination effects of nano-TiO2 and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on biotransformation gene expression in the liver of European sea bass Dicentrarchus labrax

Citation

Vannuccini ML, Grassi G, Leaver M & Corsi I (2015) Combination effects of nano-TiO2 and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on biotransformation gene expression in the liver of European sea bass Dicentrarchus labrax. Comparative Biochemistry and Physiology - Part C: Toxicology and Pharmacology, 176-177, pp. 71-78. https://doi.org/10.1016/j.cbpc.2015.07.009

Abstract
The aim of present study was to investigate the influence of titanium dioxide nanoparticles (nano-TiO2, Aeroxide® P25) on 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) dependent biotransformation gene expression in liver of juvenile European sea bass Dicentrarchus labrax. An in vivo 7 day waterborne exposure was performed with nano-TiO2(1mg/L) and 2,3,7,8-TCDD (46pg/L), singly and in combination. The mRNA expression of aryl hydrocarbon receptor repressor (Ahrr), estrogen receptor (erβ2), ABC transport proteins as Abcb1, Abcc1-c2-g2, cytochrome P450 (cyp1a), glutathione-s-transferase (gsta), glutathione reductase (gr) and engulfment and motility (ELMO) domain-containing protein 2 (elmod2) was investigated. Ahrr,erβ2,abcc1 and abcg2 resulted down-regulated with respect to controls in all experimental groups.Co-exposure to nano-TiO2 and 2,3,7,8-TCDD caused a further significant down regulation ofahrr,erβ2,Abcb1andAbcc2compared to single chemical exposure (nano-TiO2or 2,3,7,8-TCDD alone). No effects were observed for 2,3,7,8-TCDD and nano-TiO2 alone in abcb1 gene, while abcc2 was down-regulated by nano-TiO2 alone. Cyp1a,gst and elmod2 genes were up-regulated by 2,3,7,8-TCDD and to a similar extent after co-exposure. Overall the results indicate that nano-TiO2 is unlikely to interfere with 2,3,7,8-TCDD-dependent biotransformation gene expression in the liver of European sea bass, although the effects of co-exposure observed in ABC transport mRNAs might suggest an impact on xenobiotic metabolite disposition and transport in European sea bass liver.

Keywords
Titanium dioxide; Biotransformation; European sea bass; Gene expression

Journal
Comparative Biochemistry and Physiology - Part C: Toxicology and Pharmacology: Volume 176-177