Behavioural effects of early‐life exposure to parabens in zebrafish larvae

Abstract

Parabens are classified as endocrine disrupting chemicals due to their ability to activate several nuclear receptors causing changes in hormones‐dependent signalling pathways. Central nervous system of developing organisms is particularly vulnerable to changes in hormonal pathways, which could lead to altered brain function, abnormal behaviour and even diseases later in life. The aim of the present study was to investigate the effects of exposure to butylparaben (BuP), ethylparaben (EtP) and methylparaben (MeP) during early development on nervous system using zebrafish larvae's behavioural models. Zebrafish were exposed until 4 days post fertilization (dpf) to three concentrations of each paraben chosen considering the environmentally realistic concentrations of human exposure and the benchmark‐dose lower bound calculated for zebrafish larvae (BuP: 5, 50 and 500 μg/L; EtP: 50, 500 and 5000 μg/L; MeP: 100, 1000 and 10,000 μg/L). Activity in novel and in familiar environment, thigmotaxis, visual startle response and photic synchronization of the behavioural circadian rhythms were analysed at 4, 5 and 6 dpf. Zebrafish larvae exposed to BuP 500 μg/L and EtP 5000 μg/L revealed increased anxiety‐like behaviour in novel environment. Larvae treated with 500 μg/L of BuP showed reduced activity in familiar and marginally in unfamiliar environment, and larvae exposed to 5000 μg/L of EtP exhibited hyperactivity in familiar environment. Parabens exposure did not influence the visual startle response and the photic synchronization of circadian rhythms in zebrafish larvae. This research highlighted as the exposure to parabens has the potential to interfere with behavioural development of zebrafish.

Embryonic ethanol exposure induces ectopic Hcrt and MCH neurons outside hypothalamus in rats and zebrafish: Role in ethanol‐induced behavioural disturbances

“…Following the 0.0% or 0.5% ethanol treatment and ablation, zebrafish at 9 dpf underwent testing within a Noldus (Wageningen, Netherlands) DanioVision behaviour chamber to measure both anxiety-like and locomotor behaviours. 40 Behaviour was analysed for the following groups: 'Control' (no mounting or ablation) and 'Ethanol' (no mounting or ablation) to control for mounting and ablation, 'Control Mounted' (no ablation) and 'Ethanol Mounted' (no ablation) to control for mounting, 'Control AH Ablation' and 'Ethanol AH Ablation' to test the effects of ablation of normally located AH neurons and 'Ethanol POA Ablation' to test the effects of ectopic Hcrt ablation in the POA. Zebrafish were individually transferred from their home tanks into a well of a standard 12-well culture plate containing fresh embryo media, and this plate was immediately placed into the behaviour chamber.…”

Oxysterols Profile in Zebrafish Embryos Exposed to Triclocarban and Propylparaben—A Preliminary Study

“…Interestingly, in treated embryos at 24 hpf, the levels of 24-OH were higher compared with the control group. Both parabens and triclocarban have shown neurotoxicity in in vitro and in vivo studies [52,53], and the potential role of 24-OH in EDCs neurotoxicity needs further investigations.…”

Evaluation of Tacrolimus’ Adverse Effects on Zebrafish in Larval and Adult Stages by Using Multiple Physiological and Behavioral Endpoints

“…Similarly, in aquatic organisms, including fish, their vulnerability to the effects of pharmaceutical pollution may also cause circadian inactivity rhythms, which could impair their cognitive performance and swimming behavior [70][71][72]. For instance, a prior study in adult zebrafish demonstrated that chronic exposure to butyl-paraben (BuP), one of the parabens already shown to induce anxiety-like behavior in zebrafish larvae, results in circadian rhythm modulation and abnormal neurobehavioral responses to light stimulation; they later found that the explainable cause of this phenomenon is the ability of BuP to cross the blood-brain barrier and modulate the level of transcripts that are associated with phototransduction and the circadian rhythm [73,74]. Taken together, chronic exposure to tacrolimus might cause relatively minor behavior alterations in adult zebrafish in a dose-dependent manner; this requires further investigation in future studies.…”