Effect of mannitol, fenretinide, and HX 531 on DPHP-induced cardiotoxicity. Mean pericardial area (±standard deviation) (A, C, E) and mean SV-BA length (±standard deviation) (B, D, F) of 72-hpf embryos pretreated with vehicle (0.1% DMSO), 2 μM fenretinide, 5 μM HX 531, or 175 mM D-mannitol from 24 to 30 hpf and then treated with vehicle (0.1% DMSO), 1000 μM DPHP, or 20 μM TPHP from 30 to 72 hpf. Asterisk (*) denotes significant treatment effect (p < 0.05) relative to vehicle controls (0.1% DMSO), whereas single cross (†) denotes significant coexposure effect (p < 0.05) relative to embryos exposed to TPHP or DPHP alone.