The Neurobehavioral and Developmental Effects of Flame Retardants on Zebrafish

Abstract

Flame retardants are added to a large range of consumer products—including textiles, furniture, electronics and building materials—for the purpose of preventing or slowing the the spreading of fires. Human exposure to flame retardants has been shown to occur through both ingestion of indoor air and absorption of dust particles through the skin. In recent years, concern pertaining to the health and environmental implications of certain categories of flame retardants has led to the phasing out of these chemicals and replacement with alternatives, such as organophosphate (OP) flame retardants. Thus, the present study investigates whether developmental exposure to low levels of these chemicals will result in measurable behavioral effects at early or later life stages. Zebrafish eggs are exposed to flame retardant chemicals, an OP pesticide of known neurotoxicity, or a vehicle control consisting of 0.01% solution of dimethyl sulfide oxide (DMSO) for 5 days post-fertilization. After exposure, larvae swim behavior is tested. The 6-day old larvae are then transferred to aquarium water and allowed to develop normally. The adult zebrafish are tested on a battery of assessments examining anxiety-related behavior, sensorimotor integration, predatory escape, sociability, and cognitive ability. The ultimate aim is to evaluate the safety profiles of these compounds and determine whether zebrafish high throughput behavioral assays are an effective model for characterizing neurotoxicity.