Synergistic effect of a monosodium glutamate/aspartame mixture on zebrafish larval neurobehavior in comparison with the ADHD symptoms

Monosodium glutamate (MSG) and aspartame (Asp) are two of the most widely used, yet controversial food flavoring agents whose potential neurotoxicity – especially their link to childhood attention-deficit hyperactivity disorder (ADHD) – has been a debated topic for decades. In this study, we aimed to use the zebrafish (Danio rerio) embryonic model to study the possible neurobehavioral effects of these food additives and their mixture, with emphasis on their similarity to ADHD.
Our zebrafish embryo toxicity test (ZET) revealed MSG to be weakly teratogenic with a teratogenic index (TI) of 1.8 while Asp exhibited no morphological nor lethal effect on zebrafish embryos after 96 hours of exposure. Interestingly, we have found that a MSG/Asp mixture can synergistically induce zebrafish larval hyperactivity during the dark phases of alternative light-dark cycles. In parallel, we have established a zebrafish ADHD models by perfluorooctanesulfonic acid (PFOS) treatment and compare its symptoms with those induced by the food additives.
This study demonstrated that the zebrafish embryo is a cost-effective in vivo model for screening the potential neurobehavioral effects of food additives and their mixtures, as well as other chemicals. Also, our data suggest the need for more comprehensive safety assessments of food additives within the context of mixture.