Cellular, molecular and developmental biology: comparison of early life responses of zebrafish to benzo(a)pyrene and Retinoic Acid.

The zebrafish (Danio rerio) is a new model organism especially suited for early life stage developmental, molecular, and genetic toxicology. The effects of water pollution caused by the chemical output from factories, everyday activities such as driving an automobile, agricultural runoff, etc. can be analyzed with a fish-embryo life stage suite of bioassays. The compounds chosen were used to determine the points during the early life stages of a developing embryo that are most vulnerable to exposure by the two representative xenobiotics and the effects each compound will cause. Fertilized eggs were exposed to 0, 300, 400, and 500 micrograms/L of benzo(a)pyrene and 0, 400, 700, and 900 micrograms/L of Retinoic Acid. The preliminary results from this study indicate that Benzo(a)pyrene appeared to cause a light increase in average heart rate while Retinoic Acid caused a slight decrease. Also, as Retinoic Acid concentration was increased, mortality rates increased resulting in a lower percentage of embryos successfully hatching by 80 hours post fertilization; exposure to Benzo(a)pyrene resulted in an 80% hatch rate post fertilization. Even though Benzo(a)pyrene did not cause any statistical difference in mortality, curved and irregularly shaped tails and heads were observed.

Michael D. Smith*, Andrea M. Weaver, Matthew L. Duke, and Stephen J. D'Surney, University of Mississippi, Oxford, MS 38655