Toxicity of the brominated flame retardant tris-(2,3-dibromopropyl) isocyanurate in zebrafish (Danio rerio)

Abstract

Tris-(2,3-dibromopropyl) isocyanurate (TBC) is a heterocyclic brominated flame retardant that was recently detected in the environment in China. TBC is semi-volatile and can accumulate in the lipid of some species, but little is known about its effect on aquatic organisms. We exposed adult zebrafish to 0, 0.25, 1 and 4 mg/L TBC for 28 d and measured the effect on survival, growth, histopathology, hormone levels, enzyme activity, and gene expression. TBC exposure had no effect on survival or growth. We observed significant damage to the liver and gill, including hepatocellular swelling and fatty degeneration in the liver as well as proliferation and edema of epithelial cells in the gills. In addition, exposure to 4 mg/L TBC induced proliferation of goblet cells in the intestine of both sexes, acellular areas in the testis, and thinly scattered vitellogenic granules in vitellogenic oocytes. TBC exposure had no effect on the levels of thyroid hormones, testosterone, estradiol, liver superoxide dismutase activity, malondialdehyde content, and brain cholinesterase activity. By contrast, hepatic vitellogenin and cytochrome P4501A gene expression was significantly down-regulated in both male and female zebrafish in response to TBC exposure. Our results suggest that exposure to TBC causes a variety of potential reproductive and endocrine toxic effects.

Effects of tris(2,3-dibromopropyl) isocyanurate on steroidogenesis in H295R cells

“…In vitro study indicated that TBC might be one of the causative compounds inducing neuronal toxicity in the environmental samples collected near a TBC production facility (Qu et al 2011). Also, TBC has been shown to remarkably inhibit estrogen-dependent vitellogenin (VTG) gene expression in liver and further affect gonadal development in both male and female zebrafish (Zhang et al 2011). Therefore, these initial results indicate that TBC may have endocrine-disruptive effects and interference with the hormonal balance, resulting in developmental and reproductive abnormalities.…”

Influence of tris(2,3-dibromopropyl) isocyanurate on the expression of photosynthesis genes of Nannochloropsis sp.

“…TBC exposure disrupts the development and endocrine of zebrafish embryo, damages their mitochondria and interferes in their gas bladder inflation Zhang et al, 2011). It has been speculated to be toxic to neuronal cells (Qu et al, 2011).…”

Indirect competitive enzyme-linked immunosorbent assay of tris-(2,3-dibromopropyl) isocyanurate with monoclonal antibody

“…Over the past decades, halogenated flame retardants have been widely used in large volumes as additive in household products for fire safety reasons due to their excellent capability to reduce flammability. However, increasing concerns have also been raised on the environment problems caused by them, especially for brominated flame retardants (BFRs) which are widely applied to a variety of combustible materials to reduce the risk of fire damage [2][3][4].…”

“…There is evidence that TBC is semi-volatile, environmentaly persistent and has a tendency to bioaccumulate. It can be accumulated in lipid-rich organs, such as the brain, liver, intestine, etc [4]. In 2009, TBC was found, for the first time, in the natural environment around a TBC manufacturing plant in South China [2].…”

“…In 2009, TBC was found, for the first time, in the natural environment around a TBC manufacturing plant in South China [2]. Moreover, studies on zebrafish embryos suggested that exposure to TBC can cause a variety of potential reproductive and endocrine disrupting toxic effects, damaging mitochondria and causing defects in gas bladder inflation [4,6]. Thus, there is reason to be concerned about their potential to cause harm to ecosystems and human health.…”