Flame retardant tris(1,3-dichloro-2-propyl)phosphate (TDCPP) toxicity is attenuated by N-acetylcysteine in human kidney cells

Prolonged exposure to the flame retardants found in many household products and building Materials is associated with adverse developmental, reproductive, and carcinogenic consequences. While these compounds have been studied in numerous epidemiological and animal models, less is known about the effects of flame retardant exposure on cell function. This study evaluated the toxicity of the commonly used fire retardant tris(1,3-dichloro-2-propyl)phosphate (TDCPP) in cell line derived from the kidney, a major tissue target of organohalogen toxicity. TDCPP inhibited cell growth at lower concentrations (IC₅₀ 27 μM), while cell viability and toxicity were affected at higher concentrations (IC₅₀ 171 μM and 168 μM, respectively). TDCPP inhibited protein synthesis and caused cell cycle arrest, but only at higher concentrations. Additionally, the antioxidant N-acetylcysteine (NAC) reduced cell toxicity in cells treated with TDCPP, suggesting that exposure to TDCPP increased oxidative stress in the cells. In summary, these data show that low concentrations of TDCPP result in cytostasis in a kidney cell line, whereas higher concentrations induce cell toxicity. Furthermore, TDCPP toxicity can be attenuated by NAC, suggesting that antioxidants may be effective countermeasures to some organohalogen exposures.