Abstract
Purpose :
Compounds that disrupt estrogen signaling have subtle and overt effects on the visual system, though little is known about their long-term consequences. Here, we examined whether transient developmental exposure to bisphenol-A (BPA), an estrogen agonist, at key timepoints in visual system development, alters the zebrafish optomotor response (OMR).
Methods :
Zebrafish embryos (24hpf) and larvae (72hpf or 7dpf) were transiently exposed to either high (0.1uM) BPA, low (0.001uM) BPA, water, or vehicle (DMSO < 0.1%) for 24hr and then allowed to recover in system water for 1, 2, or 4wks. Young (24hr, 72hr) exposure groups were assessed for OMR changes at each timepoint; whereas, the older (7d) exposure group was assessed immediately after exposure and again after 1 and 2wk of recovery. Percentage of larvae displaying a positive OMR was statistically compared across treatment groups.
Results :
Larvae exposed at 24hpf showed statistically comparable OMRs across all groups at 1 and 2wk post-exposure; at 4wk, significantly increased OMRs were observed only in the high BPA group. Larvae exposed to high BPA at 72hpf displayed a significant increase in OMR at 1wk and 4wk post-exposure; at 2wk post-exposure the highest percentage of responders was in the low BPA group. Larvae exposed to high BPA at 7dpf had significantly more positive OMRs at the initial and 1wk timepoints. After 2wk, the OMRs of these larvae were comparable across groups. Age-dependent changes were also noted: 2wk post-exposure resulted in comparable results across groups when embryos were exposed at 24hpf, while significantly greater responses were observed in the low BPA group when exposure occurred at 72hpf, and there were significantly greater responses in both BPA groups when exposure occurred at 7dpf.
Conclusions :
Transient developmental exposure to environmentally-relevant BPA levels at critical points in vision system maturation enhances optomotor responses, suggesting a functional change. There are also age-related effects alongside treatment based effects.
This is a 2020 ARVO Annual Meeting abstract.