GSE134345
Transcriptomic analysis reveals potential mechanisms of toxicity in a combined exposure to dibutyl phthalate and diisobutyl phthalate in zebrafish (Danio rerio) ovary
Phthalate esters (PAEs), a notable plasticizer, could be prolific contaminants in the aquatic environment, and have been shown to induce reproductive toxicity. However, studies concerning the toxicity towards aquatic species are based upon individual chemicals and the combined toxicity of PAEs to aquatic organisms remains unclear. The aim of this study was to explore the potential toxic mechanism of combined exposure to dibutyl phthalate (DBP) and diisobutyl phthalate (DiBP) in adult female zebrafish ovarian. Zebrafish were exposed to DBP, DiBP and their mixtures for 30 days, and their effects on ovarian histology, plasma sex hormones and ovarian transcriptomics were investigated. The plasma estradiol (E2) levels were significantly decreased 38.9% for DBP-1133 exposure group and 41.0% for DiBP-1038 exposure group. The percentages of late/mature oocyte were also significantly decreased 17.3% in DBP-1133 exposure and 16.2% in DiBP-1038 exposure, while those in combined exposure were not significantly affected. Nonetheless, transcriptome sequencing discovered 2564 differential expressed genes (DEGs) in zebrafish ovary after exposure to the mixtures. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis identified that those DEGs were involved in the neuroactive ligand-receptor interaction, GnRH, progesterone-mediated oocyte maturation, oocyte meiosis and steroid hormone biosynthesis signaling pathways. These results revealed that combined exposure showed potential reproductive toxicity at the molecular level. Overall design: Ovarian mRNA sequencing of adult female zebrafish after single and combined exposure to DBP and DiBP for 30 days