Trans-generational effect of neurotoxicity and related stress response in Caenorhabditis elegans exposed to tetrabromobisphenol A

Abstract

Tetrabromobisphenol A (TBBPA), one of the most common brominated flame retardants, has been associated with immunotoxicity, neurotoxicity, and reproductive toxicity. However, little attention has been focused on understanding the trans-generational effects of TBBPA. The present study used the Caenorhabditis elegans (C. elegans) animal model to evaluate the trans-generational effects of neurotoxicity induced by environmentally relevant concentrations of TBBPA (0, 0.1, 1, 10, 100, and 1000 µg/L). Multiple indicators including physiological effects (body length, brood size, head thrashes, body bends, and crawling trajectory), degree of neuronal damage (dopamine, GABAergic, and glutamatergic neurons), oxidative stress-related biochemical indicators (superoxide dismutase [SOD] activity, catalase [CAT] enzyme, malondialdehyde [MDA] production, and reactive oxygen species [ROS] accumulation), and stress-related gene expressions have been evaluated in the exposed parental C. elegans generation (G1) and their progeny (G2) under TBBPA-free conditions. The results showed that TBBPA exposure induced adverse effects on physiological endpoints, among which body bends and head thrashes were the most sensitive ones, detected above 1 µg/L in G1 and 100 µg/L in G2 nematodes, respectively. After contaminant exposure, the three neurons revealed damage related to neurobehavioral endpoints, with no hereditary effects in the progeny. The oxidative stress-related biochemical endpoints demonstrated that when the exposure concentrations were above 1 µg/L in maternal worms, impairment can be detected in both generations, but the progeny recovered at low toxicity concentration (1–100 µg/L). The integrated target gene expression profiles were clearly altered in G1 and G2 worms at concentrations between 1 and 1000 µg/L, and a more significant difference existed in two generations of nematodes at low levels (1–10 µg/L) of TBBPA. Studing trans-generational neurotoxicity and the underlying mechanism can generate a precise evaluation of the environmental risk of TBBPA.