Meeting Abstract
Human and wildlife exposure to anthropogenic environmental contaminants such as dioxin-like compounds has been documented worldwide. PCB-126 (3,3’,4,4’,5-pentachlorobiphenyl) is the most toxic dioxin-like PCB congener, causing toxicity through the aryl hydrocarbon receptor pathway. There is detailed understanding of the effects and the associated mechanisms following acute exposure of adults as well as embryos to PCB-126. However, when considering the developing embryo, the levels of chemical exposure leading to delayed effects can be below those causing overt effects. Yet, the full potential for later-life health effects that result from early-life low level exposure to dioxin-like compounds is not well understood. Zebrafish are excellent tools for studying later life effects of embryonic exposure for several reasons; their short generation time is ideal for full embryo-to-adult experiments in relevant time-scales, their ex utero development and transparent embryos allow for easy evaluation of exposure levels that do not cause immediate overt effects, their easy maintenance and breeding and high fecundity allow high throughput experimentation with many biological replicates. We exposed zebrafish embryos to either DMSO (vehicle control) or a low concentration of PCB-126 (0.3 nM) starting from 4-5 hours post fertilization (hpf) until 24 hpf, and reared them to adulthood. We compared the behavior of DMSO- and PCB-126-exposed fish at several juvenile stages (6, 7 and 14 days post fertilization) and after reaching adulthood. Our study shows that early, embryonic exposure to PCB-126 causes adult behavioral changes that are not apparent at the juvenile stages.
