EGTA-induced disruption of adherens junctions in zebrafish embryonic epidermis.

Zebrafish epidermis is an accessible tissue to evaluate the impact of drugs on epithelial integrity. Although ethylene glycol-bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA E3889, Sigma-Aldrich, CABA-Argentina), a calcium chelator, is widely used to disrupt epithelial monolayers in vitro, its application to zebrafish in vivo remains limited. We found that short-term exposure to EGTA induced tail damage ranging from minor and reversible to severe and lethal; at the tissue level, it caused disruption of cadherin-mediated cell-cell contacts and of the barrier function in the epidermis. Labeling with fluorescent quantum dots (QDs) enabled rapid characterization of damage severity, evidencing the disappearance of actin microridges in the enveloping layer. At least 15 min exposure to 25 mM EGTA induces reversible epithelial disruption at the pharyngula stage, providing a chemical model to study healing and regeneration in zebrafish embryos.