Developmental toxicity and transcriptome analysis of equine estrogens in developing medaka (Oryzias latipes) using nanosecond pulsed electric field incorporation.

The research article is about the evaluation of the toxic effects of equine estrogens, hormones derived from the urine of pregnant mares, on the development of medaka fish embryos by analyzing its alterations of gene expressions.

Objective of the Research

• The primary objective of the research was to observe and analyze the possible developmental toxicity from exposure of medaka fish embryos to two types of equine estrogens known as equilin (Eq) and equilenin (Eqn). Medaka embryos were selected for the study due to their transparent eggs, which allows close examination of developmental processes.

Methodology and Results

• The researchers subjected the embryos to varying concentrations of Eq and Eqn. At certain concentrations, physical malformations were observed, including delayed hatching.
• To understand the molecular mechanisms behind these developments, a thorough transcriptome and bioinformatics analyses were undertaken.

Transcriptome and Bioinformatics Analyses

• A large number of genes were found to be differentially expressed in Eq and Eqn treated samples. Among these, a significant overlap was detected, which suggests common pathways that are affected by both Eq and Eqn.
• The Differential Expressed Genes (DEGs) were related to certain gene ontologies, including those linked to blood circulation and cell junctions, which could attribute to the physical abnormalities observed.
• Performing a pathway analysis using the DEGs revealed that treatments at certain concentrations affected several pathways enlisted in the Kyoto Encyclopedia of Genes and Genomes (KEGG). These include pathways related to neuroactive ligand-receptor interaction, mitogen-activated protein kinase signaling, retinol metabolism, and cytokine-cytokine receptor interaction.

Conclusion

• The study concluded that the developmental toxicity in the medaka embryos observed from exposure to equine estrogens is likely due to disruptions in these identified KEGG pathways.

Implications of the Study

• The research findings are important as equine estrogens are used in human medications, which could potentially have an impact on human health. Additionally, the study contributes to understanding the effect of these substances on aquatic organisms and their larger ecosystems.