title: Beta-naphthoflavone-inducedCYP1A expression in the guppy Jenynsia multidentata: Time-dependent response, anesthetic MS-222 effect and fin analysis.
abstract: Cytochrome P450 1A (CYP1A) expression in fish is used as a biomarker of exposure to organic contaminants, such PAHs, PCBs and dioxins, in the aquatic environment. South American guppy fish Jenynsia multidentata were exposed to the prototypical aryl hydrocarbon receptor (AHR) agonist beta-naphthoflavone (BNF; 1μM) and the fins were biopsied to characterize different aspects of CYP1A induction. RTq-PCR was used to quantify CYP1A mRNA levels in fish tissues. CYP1A induction in the gill, liver and anal fin (gonopodium) occurred within the first hour of waterborne exposure to BNF and persisted throughout 2, 4, 8, 24, 48 and 96h compared to controls (DMSO vehicle; p<0.05). The organ-specific temporal pattern of induction was marked by mRNA levels consistently augment as duration of exposure increases and tend to a sustained induction from 24h to 96h for gill and liver (∼15-fold and ∼50-fold over control, respectively). In gonopodium, there was a maximum CYP1A mRNA level at 4h (∼34-fold over control). Basal CYP1A mRNA levels and its induction following BNF exposure were not affected by administration of a chemical anesthetic (fish immersion in 100mgl(-1) MS-222 for 2-5min) in the gill, liver, gonopodium, dorsal or tail fin (p<0.05). In an ex vivo assay, in which small pieces of biopsied fins were exposed to BNF for 4h, high CYP1A induction was observed in the tail and gonopodium (∼49-fold and ∼69-fold, respectively) but not in the dorsal fin compared to controls. To our knowledge, this is the first study to show that a 1h waterborne exposure to an AHR agonist is sufficient to cause CYP1A induction in fish organs and fins. The present study added new information to the field regarding the use of MS-222 as an anesthetic on fish and the analysis of biopsied fins as an alternative non-lethalex vivo assay for evaluating the CYP1A biomarker in fish. This observation could be useful for planning fish toxicological bioassays and biomonitoring studies on the aquatic environments in South America.
authors.affiliation: Programa de Pós-graduação em Biologia de Ambientes Aquáticos Continentais, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande - FURG, Rio Grande, RS 96203-900, Brazil.
authors.forename: Debora P
authors.initials: DP
authors.lastname: Pinto
authors.affiliation: Programa de Pós-graduação em Biologia de Ambientes Aquáticos Continentais, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande - FURG, Rio Grande, RS 96203-900, Brazil.
authors.forename: Cíntia C
authors.initials: CC
authors.lastname: Chivittz
authors.affiliation: Programa de Pós-graduação em Biologia de Ambientes Aquáticos Continentais, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande - FURG, Rio Grande, RS 96203-900, Brazil.
authors.forename: Roger S
authors.initials: RS
authors.lastname: Ferreira
authors.affiliation: Programa de Pós-graduação em Ciências Fisiológicas - Fisiologia Animal Comparada, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande - FURG, Rio Grande, RS 96203-900, Brazil.
authors.forename: Mauricio S
authors.initials: MS
authors.lastname: Sopezki
authors.affiliation: Programa de Pós-graduação em Biologia de Ambientes Aquáticos Continentais, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande - FURG, Rio Grande, RS 96203-900, Brazil; Programa de Pós-graduação em Ciências Fisiológicas - Fisiologia Animal Comparada, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande - FURG, Rio Grande, RS 96203-900, Brazil. Electronic address: juliano.zanette@pq.cnpq.br.
authors.forename: Juliano
authors.initials: J
authors.lastname: Zanette
mesh_terms: D062365:Aminobenzoates / Q000494:pharmacology*; D000777:Anesthetics / Q000494:pharmacology*; D058500:Animal Fins / Q000187:drug effects / Q000201:enzymology; D000818:Animals; D003532:Cyprinodontiformes / Q000235:genetics / Q000378:metabolism; D019363:Cytochrome P-450 CYP1A1 / Q000096:biosynthesis* / Q000235:genetics; D005880:Gills / Q000187:drug effects / Q000201:enzymology; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D008297:Male; D012333:RNA, Messenger / Q000096:biosynthesis; D018336:Receptors, Aryl Hydrocarbon / Q000819:agonists; D014873:Water Pollutants / Q000633:toxicity*; D019324:beta-Naphthoflavone / Q000633:toxicity*
chemical_list: D062365:Aminobenzoates; D000777:Anesthetics; D012333:RNA, Messenger; D018336:Receptors, Aryl Hydrocarbon; D014873:Water Pollutants; C003636:tricaine; D019324:beta-Naphthoflavone; D019363:Cytochrome P-450 CYP1A1
keywords: CYP1A; Fish; Jenynsia multidentata; PAH; Pollution; Tricaine