Dose-Dependent Effect of Tetrabromobisphenol A-Diallyl Ether (TBBPA-DHEE) Exposure on Behavioral Alterations in Adult Zebrafish (Danio rerio)

Tetrabromobisphenol A (TBBPA) remains the most widely used flame retardant, accounting for approximately 60% of the BFR market due to its high flame retardancy, excellent heat resistance, and exceptional hydrolysis stability. Previous studies highlighted it as a potent environmental endocrine disruptor and may lead to embryonic development toxicity, neurotoxicity, reproductive toxicity, and hepatotoxicity. Among several derivatives of TBBPA, Tetrabromobisphenol A bis (2-hydroxyethyl) ether (TBBPA-DHEE) remains one of the important derivatives mainly used in the production of materials like engineering polymers, thermoplastic polyesters, laminations for electric boards, and coatings, which are highly used nowadays. Few studies have shown that it has a neurotoxic effect and causes potential neurotoxicity. However, the broader insights into its impact and doses leading to neurotoxicity and neurobehavioral impairment remain unclear. Herein, the effects of TBBPA-DHEE on the behavior of adult zebrafish were evaluated in a dose-dependent manner. The study includes adult zebrafish divided into five groups: control, DMSO as a vehicle control, and varying concentrations of TBBPA-DHEE (5 mg/L, 10 mg/L, and 20 mg/L) to examine its dose-dependent, effect over 2 weeks. Then, after the behavioral study was performed, including the open field test, novel tank test, swimming behavior test, and dark light test, results displayed that increased anxiety-like behavior, impaired memory, and decreased locomotor activity could be observed in zebrafish exposed to medium and high concentrations of TBBPA-DHEE. In contrast, low concentration didn’t display noticeable changes. The results showed a significant dose-dependent increase in neurobehavioral dysfunction, and these findings suggest that TBBPA may impair motor function, potentially through disruption of neurotransmitter systems or damage to motor neurons. Such a study provides deeper insights into TBBPA-induced significant neurobehavioral dysfunctions in zebrafish in a dose-dependent manner. It thus raises important concerns about the potential implications for human health.