title: Selenium preferentially accumulates in the eye lens following embryonic exposure: a confocal X-ray fluorescence imaging study.
abstract: Maternal transfer of elevated selenium (Se) to offspring is an important route of Se exposure for fish in the natural environment. However, there is a lack of information on the tissue specific spatial distribution and speciation of Se in the early developmental stages of fish, which provide important information about Se toxicokinetics. The effect of maternal transfer of Se was studied by feeding adult zebrafish a Se-elevated or a control diet followed by collection of larvae from both groups. Novel confocal synchrotron-based techniques were used to investigate Se within intact preserved larvae. Confocal X-ray fluorescence imaging was used to compare Se distributions within specific planes of an intact larva from each of the two groups. The elevated Se treatment showed substantially higher Se levels than the control; Se preferentially accumulated to highest levels in the eye lens, with lower levels in the retina, yolk and other tissues. Confocal X-ray absorption spectroscopy was used to determine that the speciation of Se within the eye lens of the intact larva was a selenomethionine-like species. Preferential accumulation of Se in the eye lens may suggest a direct cause-and-effect relationship between exposure to elevated Se and Se-induced ocular impairments reported previously. This study illustrates the effectiveness of confocal X-ray fluorescence methods for investigating trace element distribution and speciation in intact biological specimens.
authors.affiliation: Department of Geological Sciences, University of Saskatchewan , 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.
authors.forename: Sanjukta
authors.initials: S
authors.lastname: Choudhury
authors.forename: Jith K
authors.initials: JK
authors.lastname: Thomas
authors.forename: Nicole J
authors.initials: NJ
authors.lastname: Sylvain
authors.forename: Olena
authors.initials: O
authors.lastname: Ponomarenko
authors.forename: Robert A
authors.initials: RA
authors.lastname: Gordon
authors.forename: Steve M
authors.initials: SM
authors.lastname: Heald
authors.forename: David M
authors.initials: DM
authors.lastname: Janz
authors.forename: Patrick H
authors.initials: PH
authors.lastname: Krone
authors.forename: Ian
authors.initials: I
authors.lastname: Coulthard
authors.forename: Graham N
authors.initials: GN
authors.lastname: George
authors.forename: Ingrid J
authors.initials: IJ
authors.lastname: Pickering
mesh_terms: D000818:Animals; D005260:Female; D007814:Larva; D007908:Lens, Crystalline / Q000378:metabolism*; D018811:Maternal Exposure; D061848:Optical Imaging; D012643:Selenium / Q000493:pharmacokinetics*; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics*; D056928:X-Ray Absorption Spectroscopy; D015027:Zebrafish
chemical_list: D014874:Water Pollutants, Chemical; D012643:Selenium