Abstract :
[en] Background information: There are rising concerns about potential hazardous properties of food additives, forcing legislator to tighten management policy and requiring extensive, yet animal- minimized, testing strategies. The zebrafish embryo is an emerging model system for chemical testing with many advantages that made it amenable to high-throughput assays at the in vivo level. In this study, we applied a panel of tests to evaluate toxicity, particularly neurobehavioral effects, of seven substances including standard compounds and controversial food additives.
Methods: Zebrafish wildtype and transgenic fluorescent embryos were exposed to different concentrations of four food additives: Sodium benzoate (SB), Monosodium glutamate (MSG), Tartrazine (TTZ), and Quinoline yellow (QY). Method validation was carried out using three other substances: Ethanol (EtOH), Dimethyl sulfoxide (DMSO), 3,4-Dichloroaniline (DCA). Morphological and lethal effects were recorded and the data were analysed to determine median lethal concentration (LC50), median effective concentration (EC50), effective concentration 10% (EC10), and teratogenic index (TI) values as well as concentration-response equations. Delayed effects of substances on larval locomotion were inspected using the light/dark challenge. Gene expression analysis was carried out using transgenic fluorescent lines.
Results: LC50 values of three standard compounds (EtOH, DMSO, and DCA) reveal a high correlation with previously validated data, proving the reliability of our method. Effects of each substance on zebrafish embryonic morphology and lethality were determined as well as the corresponding concentration-response curves. Calculated toxicological indexes revealed that SB belongs to Cat.3 aquatic toxicity class, while QY is the most teratogenic substance. At EC10, all additives exhibited a delayed effect on zebrafish larval locomotion in compound-specific patterns. Observation of transgenic fluorescent embryos and locomotion analysis of hatched larvae reveal that SB could decrease the zebrafish motoneuron differentiation rate, while TTZ exhibited anti-angiogenic effects.
Conclusion: Our results demonstrate that our test panel is reliable as a means to assess and categorise chemical toxicity. Also, our data suggest the need to reconsider the safety of food additives SB, TTZ, and QY as well as other controversial food additives in further studies.
