title: A novel in vitro system for the determination of bioconcentration factors and the internal dose in zebrafish (Danio rerio) eggs.
abstract: In this study a novel in vitro approach for the determination of bioconcentration factors (BCF) and rate constants of lipophilic substances utilizing zebrafish (Danio rerio) eggs is presented. Zebrafish eggs were exposed in a static exposure regime towards a phenanthrene solution and concentration-time profiles of the exposure solutions were analyzed over time. The rate constants and the BCF were obtained from the concentration-time profile with the use of a least-square fit to a non-linear model. The determined BCF at steady-state (after 72h of exposure) for phenanthrene was estimated to be only about 1.5 times lower, than the respective BCF value reported in the literature. For uptake of solutes in zebrafish embryos, different transport processes are assumed as substances have to pass the chorion first and subsequently the membranes of the embryo. To investigate this, the period to steady-state concentration between zebrafish eggs and the ambient medium for phenanthrene under an agitated and non-agitated static exposure regime were compared. It was found, that this equilibrium was reached within a shorter time frame under agitation, resulting in higher rate constants. In addition to the determination of bioconcentration parameters, the internal phenanthrene dose in zebrafish eggs was determined by utilizing a biomimetic extraction method with water as transfer medium. Approximately 55% of the expected accumulated phenanthrene amount in zebrafish eggs could be re-extracted with a silicone rod extraction method. These results agree very well to what has been observed in abiotic systems. The scope of the proposed in vitro protocol to serve as an alternative for BCF determinations using established in vivo animal testing protocols with adult fish is discussed.
authors.affiliation: UFZ-Helmholtz Centre for Environmental Research, Department Bioanalytical Ecotoxicology, Permoserstrasse 15, 04318 Leipzig, Germany. rene.schreiber@ufz.de
authors.forename: René
authors.initials: R
authors.lastname: Schreiber
authors.forename: Rolf
authors.initials: R
authors.lastname: Altenburger
authors.forename: Albrecht
authors.initials: A
authors.lastname: Paschke
authors.forename: Gerrit
authors.initials: G
authors.lastname: Schüürmann
authors.forename: Eberhard
authors.initials: E
authors.lastname: Küster
mesh_terms: D000818:Animals; D004625:Embryo, Nonmammalian / Q000187:drug effects*; D007700:Kinetics; D008956:Models, Chemical; D010616:Phenanthrenes / Q000032:analysis* / Q000633:toxicity; D018570:Risk Assessment; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity; D015027:Zebrafish / Q000196:embryology*
chemical_list: D010616:Phenanthrenes; D014874:Water Pollutants, Chemical; C031181:phenanthrene