Embryotoxic and pharmacologic potency ranking of six azoles in the rat whole embryo culture by morphological and transcriptomic analysis

Journal Article · Mon May 01 04:00:00 EDT 2017 · Toxicology and Applied Pharmacology

DOI:https://doi.org/10.1016/J.TAAP.2017.03.001· OSTI ID:22690961

Dimopoulou, Myrto ^[1]; Verhoef, Aart; Pennings, Jeroen L.A. ^[2]; Ravenzwaay, Bennard van ^[1]; Piersma, Aldert H. ^[2]

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1. Division of Toxicology, Wageningen University (Netherlands)
2. National Institute of Public Health and the Environment (RIVM), Bilthoven (Netherlands)

Differential gene expression analysis in the rat whole embryo culture (WEC) assay provides mechanistic insight into the embryotoxicity of test compounds. In our study, we hypothesized that comparative analysis of the transcriptomes of rat embryos exposed to six azoles (flusilazole, triadimefon, ketoconazole, miconazole, difenoconazole and prothioconazole) could lead to a better mechanism-based understanding of their embryotoxicity and pharmacological action. For evaluating embryotoxicity, we applied the total morphological scoring system (TMS) in embryos exposed for 48 h. The compounds tested showed embryotoxicity in a dose-response fashion. Functional analysis of differential gene expression after 4 h exposure at the ID{sub 10} (effective dose for 10% decreased TMS), revealed the sterol biosynthesis pathway and embryonic development genes, dominated by genes in the retinoic acid (RA) pathway, albeit in a differential way. Flusilazole, ketoconazole and triadimefon were the most potent compounds affecting the RA pathway, while in terms of regulation of sterol function, difenoconazole and ketoconazole showed the most pronounced effects. Dose-dependent analysis of the effects of flusilazole revealed that the RA pathway related genes were already differentially expressed at low dose levels while the sterol pathway showed strong regulation at higher embryotoxic doses, suggesting that this pathway is less predictive for the observed embryotoxicity. A similar analysis at the 24-hour time point indicated an additional time-dependent difference in the aforementioned pathways regulated by flusilazole. In summary, the rat WEC assay in combination with transcriptomics could add a mechanistic insight into the embryotoxic potency ranking and pharmacological mode of action of the tested compounds. - Highlights: • Embryonic exposure to azoles revealed concentration-dependent malformations. • Transcriptomics could enhance the mechanistic knowledge of embryotoxicants. • Retinoic acid gene set identifies early embryotoxic responses to azoles. • Toxic versus pharmacologic potency determines functional efficacy.

• OSTI ID: 22690961
• Journal Information: Toxicology and Applied Pharmacology, Journal Name: Toxicology and Applied Pharmacology Vol. 322; ISSN TXAPA9; ISSN 0041-008X
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
ABUNDANCE
AZOLES
BIOSYNTHESIS
CONCENTRATION RATIO
EMBRYOS
FUNCTIONAL ANALYSIS
GENES
MALFORMATIONS
ONTOGENESIS
RADIATION DOSES
RATS
RETINOIC ACID
STEROLS
TIME DEPENDENCE
TOXICITY