title: 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.
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 7day 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 of ahrr, erβ2, Abcb1 and Abcc2 compared to single chemical exposure (nano-TiO2 or 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.
authors.affiliation: Department of Physical, Earth and Environmental Sciences, University of Siena, Siena, Italy.
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Vannuccini
authors.affiliation: Department of Physical, Earth and Environmental Sciences, University of Siena, Siena, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Grassi
authors.affiliation: Institute of Aquaculture, University of Stirling, Stirling, United Kingdom.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Leaver
authors.affiliation: Department of Physical, Earth and Environmental Sciences, University of Siena, Siena, Italy. Electronic address: ilaria.corsi@unisi.it.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Corsi
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001492:Bass / Q000235:genetics / Q000378:metabolism*; D001711:Biotransformation; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D053768:Metal Nanoparticles; D010316:Particle Size; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D012333:RNA, Messenger / Q000378:metabolism; D014025:Titanium / Q000633:toxicity*
chemical_list: D018528:ATP-Binding Cassette Transporters; D029941:Fish Proteins; D000072317:Polychlorinated Dibenzodioxins; D012333:RNA, Messenger; C009495:titanium dioxide; D014025:Titanium
keywords: Biotransformation; European sea bass; Gene expression; Titanium dioxide