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2,3,7,8-TCDD effects on visual structure and function in swim-up rainbow trout
Paulo S M Carvalho1, Donald E Tillitt
1Columbia Environmental Research Center, United States Geological Survey, Columbia, Missouri 65201, USA. pcarvalho@ccb.ufsc.br
Environmental Science & Technology
|December 16, 2004
Summary
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) exposure in rainbow trout caused dose-dependent decreases in retinal ganglion cells, impairing vision and foraging behavior. These effects highlight TCDD
Area of Science:
- Ecotoxicology
- Neuroscience
- Environmental Health
Background:
- Understanding contaminant effects across biological levels is crucial for predictive ecotoxicology.
- Assessing impacts on visual function and behavior informs population-level risk.
Purpose of the Study:
- To evaluate the effects of 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) on visual structure, function, and foraging behavior in rainbow trout.
- To link biochemical and histological changes to behavioral deficits.
Main Methods:
- Biochemical, histological, and behavioral assays were used.
- Assessed retinal ganglion cell (RGC) density, visual acuity, scotopic/photopic thresholds, and prey capture rates.
- Measured CYP1A protein levels via immunohistochemistry.
Main Results:
- TCDD caused a dose-dependent decrease in RGC density.
- Visual deficits, including reduced acuity and altered light thresholds, were observed.
- CYP1A protein levels increased proportionally with RGC loss.
- Prey capture rates decreased at the highest TCDD exposure levels.
Conclusions:
- TCDD induces biochemical and structural changes in trout eyes and brains.
- These changes correlate with behavioral deficits and reduced individual fitness.
- AHR-regulated pathways may mediate TCDD's neurotoxic effects on vision.