Professor of Biology Carleton College Northfield, Minnesota, United States
Disclosure(s):
Debby Walser-Kuntz, PhD: No financial relationships to disclose
Introduction/Rationale: Bisphenol A (BPA), a widely used component for polycarbonate plastic production, is often found in surface water and wastewater runoff. BPA disrupts estrogen activity of humans and wildlife by binding to ERα and β, modulating both reproduction and immunity. Previously, we found BPA-exposed zebrafish larvae had decreased fin regeneration and neutrophil recruitment following a caudal fin injury. Hydrogen peroxide (H2O2) generation is tightly regulated and essential for initiation of wound healing, neutrophil migration, and regeneration. Based on work suggesting BPA upregulated NADPH oxidase in other species, we hypothesized BPA modulated H2O2 production and expression of key regeneration-related genes at the site of injury, thus affecting wound healing.
Methods: MPX:GFP zebrafish were continuously exposed to 100ng/ml BPA or egg water from 0-7 days post fertilization (dpf) and a caudal fin injury was induced 4 dpf. We measured H2O2 generation immediately and from 3-72 hours post-injury (hpi) in live, agarose-mounted larvae using CellMeter Hydrogen Peroxide probe and confocal microscopy. Mean fluorescence intensity was quantified using ZEN Blue image analysis. We extracted RNA from 3-72 hpi and performed qPCR to evaluate the expression of vegfa, mmp-9, tgf-beta, and il-1b; beta-actin and rpl-13a were used as reference genes. We extracted RNA from uninjured fish 2-7 dpf to assess variation in baseline expression of these genes.
Results: We observed an increase in H2O2 at the site of injury in BPA-treated larvae. We found BPA treatment modulated the expression of key genes involved in wound healing and tissue regeneration in response to caudal fin injury, including mmp-9. The baseline expression of mmp9 as well as most genes tested was not affected by BPA exposure, with the exception of some cytokines such as il-1b, which was more highly expressed in BPA-treated larvae.
Conclusion: We find that BPA exposure in zebrafish larvae dysregulated functions essential for proper wound healing.
