Molecular mechanisms of developmental toxicity induced by BBP in zebrafish embryos

Butylbenzyl phthalate (BBP) has been shown to negatively affect the development of zebrafish embryos, however, its underlying mechanisms remain unclear. Therefore, our study aims to reveal the molecular mechanisms of developmental toxicity on zebrafish embryos. Zebrafish embryos were exposed to BBP (0, 0.6, and 1.2 mg/L) from 4 to 72 h post-fertilization (hpf). The adverse effects on zebrafish embryos were evaluated and the transcriptional profiles of zebrafish embryos were analyzed at 72hpf. Exposure to BBP decreased hatching and survival rates and induced obvious morphology abnormalities in zebrafish embryos. The activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) significantly decrease and the malondialdehyde (MDA) content significantly increased with 1.2 mg/L BBP exposure. Global transcriptome profiling analysis demonstrated that 578 and 1257 genes were differentially expressed in zebrafish embryos in the 0.6 and 1.2 mg/L groups, respectively. Gene Ontology (GO) term enrichment analysis demonstrated that DEGs are related to many aspects of cell composition, biological processes, and molecular functions. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis demonstrated that 13 and 22 pathways were significantly enriched in the 0.6 and 1.2 mg/L groups, respectively. DEGs were primarily concentrated in the metabolism of the 0.6 mg/L group and in the organismal systems and particularly affected vision and digestion in the 1.2 mg/L group. Our results contribute to a better understanding of the underlying mechanisms of developmental toxicity induced by phthalates.