Embryos, with and without injection of THRβ mRNA at the 1–2 cell stage, were exposed to 0 (control), 1,10, 50 or 100 nM 6-OH-BDE-47 from 4 to 26 hpf. At 26 hpf, embryos were sectioned and TUNEL stained. TUNEL-positive, brown colored cells (i.e., apoptotic cells), were in the brain (red arrows) where they increased in a concentration-dependent manner after 6-OH-BDE-47 exposure (A–E). This effect was rescued by overexpression of THRβ mRNA (F–J). All images are at the same magnification, scale bars are 100 mm. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)