PUBLICATION

The aquatic vertebrate embryo as a sentinel for toxins: zebrafish embryo dechorionation and perivitelline space microinjection

Authors
Mizell, M. and Romig, E.S.
ID
ZDB-PUB-970804-1
Date
1997
Source
The International journal of developmental biology   41(2): 411-423 (Journal)
Registered Authors
Mizell, Merle, Romig, Eric
Keywords
none
MeSH Terms
  • Abnormalities, Drug-Induced/veterinary
  • Animals
  • Benzene/administration & dosage
  • Benzene/toxicity
  • Cardiovascular System/drug effects
  • Cardiovascular System/embryology
  • Chorion/physiology*
  • Embryo, Nonmammalian/drug effects*
  • Fish Diseases/chemically induced
  • Gastrula/drug effects
  • Hexachlorobenzene/administration & dosage
  • Hexachlorobenzene/toxicity
  • Microinjections
  • Oryzias/embryology*
  • Toluene/administration & dosage
  • Toluene/toxicity
  • Vitelline Membrane
  • Water Pollutants/administration & dosage*
  • Water Pollutants/toxicity
  • Zebrafish/embryology*
PubMed
9184351
Abstract
Pollution of aquatic ecosystems poses a serious threat to aquatic organisms and ultimately the entire ecosystem. Understanding how a toxin affects embryonic development is key to determining the risk a pollutant represents to the environment. Extraembryonic membranes, such as the chorion of fish eggs, provide a protective barrier between the embryo and the environment. Although the fish chorion excludes many chemical pollutants, some noxious agents can still gain access to the aquatic embryo. Therefore a monitoring system that tests the effects directly upon the embryo must be established. Although exposure to a single toxin in the laboratory can determine the concentration at which a pollutant becomes a health or environmental hazard, embryos and adults in nature are not merely affected by a single chemical, but are exposed to mixtures of different pollutants. Zebrafish (Danio rerio) and medaka (Oryzias latipes) embryos were employed for the rapid observation of the effects of single chemicals and chemical mixtures on development. Using dechorionation and a perivitelline space microinjection system, the embryos were effective sentinels for low concentrations of aquatic pollutants. The developmental effects of small quantities of toxins were observed. Embryos treated during the late gastrula stage of development with hexachlorobenzene (HCB); 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD); toluene; benzene; or mixtures of these chemicals developed cardiovascular abnormalities. The zebrafish dechorionation exposure technique, Micro Intrachorionic Zebrafish Embryo Live Laboratory test, was especially effective in testing the pollutant mixtures. Combinations of both TCDD and benzene (as well as the toluene and benzene combinations) were tested and the mixtures acted synergistically; the combinations were more toxic than either chemical by itself. Hexachlorobenzene- and TCDD-treated embryos tested positively for expression of cytochrome P450 1A indicating that the cytochrome metabolic pathways were already functional in these early embryos, and suggested that a product of the cytochrome system may be involved in HCB and TCDD pollution associated cardiovascular defects.
Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping