Developmental, Behavioral and Transcriptomic Changes in Zebrafish Embryos after Smoke Dye Exposure

Abstract

(1) Background: Disperse Blue 14, Disperse Red 9, Solvent Red 169 and Solvent Yellow 33 have been used to color smoke; however, they have not been comprehensively assessed for their potential health hazards. (2) Methods: To assess the effects of these dyes, zebrafish embryos were exposed from 6 to 120 h post fertilization (hpf) to 10–55 µM Disperse Red 9, 1–50 µM Solvent Red 169, 7.5–13.5 µM Solvent Yellow 33 or 133–314 µM Disperse Blue 14. Embryos were monitored for adverse effects on gene expression at 48 hpf as well as for mortality, development and behavior at 120 hpf. The dyes were examined for their potential to cross the blood–brain barrier. (3) Results: Solvent Yellow 33 and Disperse Blue 14 impaired development and behavior at all concentrations. Disperse Red 9 impaired behavior at all concentrations and development at all concentrations except for 10 µM. Solvent Red 169 caused no effects. Mortality was only seen in Disperse Blue 14 at 261.5 and 314 µM. Gene expression indicated impacts on neurodevelopment and folate and retinol metabolism as potential mechanisms of toxicity. (4) Conclusions: Smoke dyes have a high potential for causing developmental changes and neurotoxicity and should be examined more closely using comprehensive approaches as used here.

Discovering Novel Bioactivities of Controversial Food Additives by Means of Simple Zebrafish Embryotoxicity (ZET) Assays

“…It should be noted that while QY may interfere with yolk metabolism, the darkened yolk phenotype mostly occurred at very high concentration, thus more likely to be related to the ionic effect rather than a consequence of disrupted lipoprotein biogenesis as shown in other studies [ 58 , 59 ]. Regarding the ophthalmic effect, a recent study on the transcriptomic effect of a QY’s unsulfonated form (Quinoline Yellow SS, Solvent Yellow 33) also reported the downregulation of metabolic genes in zebrafish embryos- especially the disruption of the retinoic acid signaling pathway, which may impair eye development [ 22 ].…”

“…Additionally, the fish’s high fecundity and low maintenance cost offer the prospects for developing high-throughput assays [ 16 , 17 , 18 ]. These advantages have made the zebrafish embryotoxicity test (ZET) an increasingly recognized tool in chemical safety screening for both environmental and biomedical applications [ 18 , 19 , 20 , 21 , 22 ].…”

“…Over the years, the zebrafish embryotoxicological toolbox has been supplemented with various advanced techniques, such as transgenic reporter lines or automated phenotyping [ 23 , 24 , 25 ] to increase experimental throughput and simplify training, or-omics tools such as RNA-Seq [ 22 , 26 ] that enable researchers to explore the mechanisms involved in a chemical’s bioactivity. These methods, while screening for chemicals’ toxicity, often mainly focus on preset endpoints, such as lethality, simple morphological defects, or expression of a reporter gene.…”

“…However, one big advantage of the embryonic zebrafish model is that specific phenotypes induced by a chemical can give hints to the underlying biological process, which is extremely important when it comes to the safety assessment of chemicals. Following up on unexpected phenotypes observed in zebrafish embryos may serve as the starting point for mechanistic studies on toxico-/pharmacology [ 22 , 26 , 27 , 28 ].…”

Advancing statistical treatment of photolocomotor behavioral response study data

“…Alternatively, it may be repeated several times for each individual light/dark period itself [ 9 – 11 ]. When assumptions for univariate one-way ANOVA are not met, Fisher’s Exact test [ 12 ] or the nonparametric Kruskal-Wallis test [ 4 , 13 , 14 ] are often used. Other approaches include repeated measures ANOVA [ 15 , 16 ]; multiple t -tests for each level of the factor against the control group [ 17 ]; t -tests for every time point [ 18 ]; and a Kolmogorov-Smirnov test comparing the area under the curve (AUC) of differential entropy between treatment and control groups [ 14 , 19 ].…”