Figure 1.

Cytotoxicity of organophosphate esters (OPEs) and 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) in KGN human granulosa cells (A and D), MA-10 mouse Leydig cells (B and E), C18-4 mouse spermatogonial cells (C and F). Cells were exposed to one of the chemicals for 48 h; numbers of Hoechst 33342 stained nuclei were quantified using Operetta high-content imaging system (40× magnification). Nonlinear regression analyses were conducted to estimate the IC₅₀ values of the test chemicals (D–F). Most of the OPEs exhibited similar or higher cytotoxicity than BDE-47 on the 3 cell lines with the exception of tris(2,4-di-tert-butylphenyl) phosphate (TDtBPP), tris(2-butoxyethyl) phosphate (TBOEP), and tris(1-chloro-2-propyl) phosphate (TCIPP). Data are shown as percentages relative to controls; values represent means ± SEM; n = 6–8. Abbreviation: N/A, not available/applicable.