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Post-Larval Developmental Trajectory of Zebrafish Fry is Altered by Exposure to T3 or T4 Analogues
Citation:
Korest, D., S. Wesstrom, D. Hunter, AND S. Padilla. Post-Larval Developmental Trajectory of Zebrafish Fry is Altered by Exposure to T3 or T4 Analogues. Carollinas SETAC, Durham, North Carolina, April 25 - 27, 2018.
Impact/Purpose:
The thyroid axis plays a key role in development. While the impacts of perturbing thyroid axis development and/or function are documented in embryonic and larval zebrafish, the effects on developmental milestones at later life stages are not well-delineated. we found that developmental exposure to non-embryotoxic concentrations of the thyroid hormone analogs TRIAC or Tetrac caused significant effects at later life stages, possibly via perturbation of the developmental trajectory of the thyroid axis.
Description:
The thyroid axis plays a key role in development. While the impacts of perturbing thyroid axis development and/or function are documented in embryonic and larval zebrafish, the effects on developmental milestones at later life stages are not well-delineated. To assess potential later life effects, zebrafish were exposed to 3,3’,5,5’-tetraiodothyroacetic acid (Tetrac; 0, 1.7, 5.44, or 17.0 nM) or Tiratricol (TRIAC; 0, 1, or 10 nM), analogues of the thyroid hormones T3 or T4, respectively, on day 0 and day 3. On day 5, larvae were transferred to vehicle-only solution (depuration) and maturation was tracked until 14 days post fertilization. Fry were assessed (n=6/day) on days 10 through 14 for body length and visual (blinded) assessment of anterior swim bladder formation and separation. Exposure to 1 nM TRIAC accelerated ASB development at 11 days, whereas exposure to 10 nM TRIAC caused a 7.2% decrease in length on days 10 through 14 and depressed anterior swim bladder development at 13 days and 14 days. Tetrac caused a similar acceleration of anterior swim bladder development in larvae exposed to 5.44 nM or 17.0 nM, while exposure to 17.0 nM Tetrac depressed anterior swim bladder development at 13 days and 14 days. No behavioral differences were noted in a locomotor test in Tetrac-treated groups at 6 or 13 days. In contrast, zebrafish exposed to 10 nM TRIAC exhibited hyperactivity at 13 days. In sum, developmental exposure to non-embryotoxic concentrations of the thyroid hormone analogs TRIAC or Tetrac caused significant effects at later life stages, possibly via perturbation of the developmental trajectory of the thyroid axis. This abstract may not necessarily reflect official Agency policy.