Combined toxicity assessment of a naturally occurring toxin and a triazole fungicide on different biological processes through toxicogenomic data mining with mixtures

Abstract

Fungicides are widely used to prevent fungal growth and reduce mycotoxin contamination in food, which provides the opportunity for the co-occurrence of mycotoxins and fungicide residues in food and poses a greater risk to human health. To assess the combined effects of a naturally occurring mycotoxin, citrinin (CIT), and a widely used triazole fungicide, triadimefon (TAD) on different biological processes, the comparative toxicogenomics database was used to obtain phenotypes and response genes for CIT or TAD exposure. Then individual and combined exposure models were developed with zebrafish embryos, and the interaction between CIT and TAD was analyzed using the 2 × 2 factorial design approach to observe the toxic effects. Through data mining analysis, our results showed that CIT or TAD exposure is related to different biological phenotypes, such as cell death, regulation of antioxidant systems, and thyroid hormone metabolism. Our results also showed that CIT (4-day LC₅₀ value of 12.7 mg/L) exposure possessed higher toxicity to zebrafish embryos compared with TAD (4-day LC₅₀ value of 29.6 mg/L). Meanwhile, individual exposure to CIT and TAD altered the expression levels of biomarkers related to oxidative stress, inflammation, apoptosis and hypothalamic-pituitary-thyroid (HPT) axis. Notably, combined exposure to CIT and TAD induced changes in the mentioned biological processes and had an interactive effect on the expression of multiple biomarkers. In conclusion, we evaluated the toxic effects of CIT and TAD in isolation and combination by in-vivo experiments, which provide a new methodological basis and reference for future risk assessment and setting of safety limits for foodborne toxicants.

Keywords: Biological processes; Citrinin; Combined toxicology; Interaction; Triadimefon.