Embryonic exposures to chemicals acting on brain aromatase lead to different locomotor effects in zebrafish larvae

Pathways underlying neurodevelopmental effects of endocrine disruptors (EDs) remain poorly known. Expression of brain aromatase (aroB), responsible for estrogen production in the brain of teleosts, is regulated by estrogenic EDs and could play a role in their behavioral effects. We exposed zebrafish eleutheroembryos (0-120 h post-fertilization) to various concentrations of 16 estrogenic chemicals (incl. bisphenols and contraceptives), and of 2 aroB inhibitors. Behavior was monitored using a photomotor response test procedure. Both aroB inhibitors (clotrimazole and prochloraz) and a total of 6 estrogenic EDs induced significant behavioral alterations, including DM-BPA, BPC and BPS-MPE, three bisphenol substitutes which behavioral effects were, to our knowledge, previously unknown. However, no consensus was reported on the effects among tested substances. It appears that behavioral changes could not be linked to groups of substances defined by their specificity or potency to modulate aroB expression, or by their structure. Altogether, behavioral effects of estrogenic EDs in 120 h post-fertilization larvae appear unrelated to aroB but are nonetheless not to be neglected in the context of environmental safety.

Automated summary

This study found that exposure to various estrogenic endocrine disruptors (EDs) can cause behavioral alterations in zebrafish during the embryonic period, including three previously unknown bisphenol substitutes. However, there is currently no consensus on the effects of these substances. Although these behavioral changes are unrelated to the specificity or structure of substances that regulate brain aromatase (aroB), the behavioral effects of estrogenic EDs should not be neglected in the context of environmental safety.