Antioxidant protection against 6-OHDA-induced dopaminergic cell death in zebrafish embryos. (a) Zebrafish embryos at 24 hours post-fertilisation (hpf) were treated with 6-OHDA for 24 hours in the presence or absence of the antioxidants Proxison or quercetin (10 μM). Embryos were then fixed at 48 hpf, immunostained for TH (red) and confocal images were taken of the embryo head viewed from the top. Scale bar: 50 μm. (b) The number of TH-positive cells in each embryo was counted for each treatment group (control, n = 28; vehicle, n = 30; Proxison, n = 26, quercetin, n = 24). Bars represent the mean number of TH-positive cells and error bars show the SEM. ANOVA with Tukey’s post-hoc test was performed to assess the significant difference to the 6-OHDA treated embryos; *p < 0.05, ***p < 0.001.