title: A new in vitro screening bioassay for the ecotoxicological evaluation of the estrogenic responses of environmental chemicals using roach (Rutilus rutilus) liver explant culture.
abstract: There is growing evidence that many chemicals released in the environment are able to disturb the normal endocrinology of organisms affecting the structure and function of their reproductive system. This has prompted the scientific community to develop appropriate testing methods to identify active compounds and elucidate mechanisms of action. Of particular interest are in vitro screening methods that can document the effects of these endocrine disrupting compounds on fish. In this study, an in vitro bioassay was developed in the roach (Rutilus rutilus) for evaluating the estrogenicity or antiestrogenicity potency of environmental pollutants by measuring vitellogenin (VTG) induction in cultured liver explants. The cell viability was assessed by the measurement of nonspecific esterase activity using a fluorescein diacetate hydrolysis assay. Results showed that explants could be cultured for 72 h without any significant loss of activity. Dose-dependent responses have been measured with estrogenic model compounds such as 17-β-estradiol (E2) and 17-α-ethynylestradiol (EE2) or antiestrogenic compounds such as tamoxifen. Lowest observable effective concentrations were 1 nM for E2, 1 nM for EE2, and 100 nM for tamoxifen, showing a good sensitivity of the test system. Estrogenicity of butyl 4-hydroxybenzoate, 4-nonylphenol, and bisphenol A was tested. bisphenol A (100 μM) or butylparaben induced a twofold increase in VTG production when compared with 100 nM E2, whereas this production was only 20% with 100 μM 4-nonylphenol. Overall, this study shows that the bioassay could provide valuable information on endocrine disrupting chemicals including metabolites and mixtures of compounds.
authors.affiliation: Laboratory of Ecotoxicology, UPRES-EA 3222, University of Le Havre, BP 540, 76058 Le Havre, France. marie.gerbron@univ-lehavre.fr
authors.forename: Marie
authors.initials: M
authors.lastname: Gerbron
authors.forename: Perrine
authors.initials: P
authors.lastname: Geraudie
authors.forename: Jeanette
authors.initials: J
authors.lastname: Rotchell
authors.forename: Christophe
authors.initials: C
authors.lastname: Minier
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods*; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism; D003530:Cyprinidae / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D054750:Ecotoxicology / Q000379:methods*; D052244:Endocrine Disruptors / Q000633:toxicity*; D004785:Environmental Pollutants / Q000737:chemistry / Q000633:toxicity*; D020847:Estrogen Receptor Modulators / Q000633:toxicity; D004967:Estrogens / Q000633:toxicity; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D009924:Organ Culture Techniques; D010636:Phenols / Q000633:toxicity; D014819:Vitellogenins / Q000633:toxicity
chemical_list: D052244:Endocrine Disruptors; D004785:Environmental Pollutants; D020847:Estrogen Receptor Modulators; D004967:Estrogens; D010636:Phenols; D014819:Vitellogenins; D002265:Carboxylic Ester Hydrolases; C041594:4-nonylphenol