Acute high-dose acesulfame exposure induces developmental and neurobehavioral toxicity.

BACKGROUND: Acesulfame potassium (ACE) is a widely used low-calorie artificial sweetener that is frequently detected in aquatic environments. Although previous studies have documented metabolic, oxidative, and behavioral effects of ACE, its developmental and neurobehavioral effects during early life stages remain insufficiently characterized. This study investigated the developmental and neurobehavioral effects of acute high-dose ACE exposure in zebrafish larvae and explored potential molecular pathways associated with these effects. METHODS: Zebrafish embryos and larvae were exposed to ACE at 100, 200, 400, and 800 mg/L for up to 144 h. Developmental phenotypes, locomotor behavior, sensorimotor responsiveness, and motor neuron morphology were evaluated. Motor neuron morphology was assessed using Tg(hb9) transgenic zebrafish. PPI network and KEGG pathway enrichment analyses were performed to prioritize candidate molecular pathways, followed by qPCR assessment of selected apoptosis-associated genes. RESULTS: Acute high-dose ACE exposure was associated with developmental abnormalities. Larvae exposed to 400 and 800 mg/L ACE showed reduced swimming distance and speed, increased immobility, and attenuated responses to light-dark transitions and mechanical stimulation. At 144 hpf, exposure to 800 mg/L ACE was also associated with shortened motor neuron synaptic length. Network analysis identified apoptosis-related pathways and prioritized casp3 as a candidate hub gene. Consistent with these findings, qPCR revealed significant alterations in several apoptosis-associated genes. CONCLUSIONS: Acute high-dose ACE exposure was associated with developmental and neurobehavioral abnormalities and altered motor neuron morphology in zebrafish larvae. The apoptosis-related signaling may contribute to the response to ACE exposure, with CASP3 identified as a candidate hub rather than a functionally validated mediator. Because the experimental concentrations substantially exceeded typical environmental exposure levels, these findings should be interpreted as acute high-dose hazard-characterization evidence rather than a direct assessment of environmental risk. Further studies using environmentally relevant chronic exposure conditions and mechanistic validation are warranted.