Functional knockout of the Oatp1d1 membrane transporter affects toxicity of diclofenac in zebrafish embryos.

Organic anion transporting polypeptides (OATPs) facilitate the cellular uptake of a large number of compounds. Zebrafish Oatp1d1 matches the functional capabilities of human OATP orthologs, particularly in hormone and drug transport. It is highly expressed in the liver and later stages of embryonic development, indicating its critical role in zebrafish physiology and development.

Stage-dependent localization of F-actin and Na /K -ATPase in zebrafish embryos detected using optimized cryosectioning immunostaining protocol.

The increasing use of the zebrafish model in biomedical and (eco)toxicological studies aimed at understanding the function of various proteins highlight the importance of optimizing existing methods to study gene and protein expression and localization in this model. In this context, zebrafish cryosections are still underutilized compared with whole-mount preparations. In this study, we used zebrafish embryos (24-120 hpf) to determine key factors for the preparation of high-quality zebrafish cryosections and to determine the optimal protocol for (immuno)fluorescence analyses of Na /K -ATPase and F-actin, across developmental stages from 1 to 5 dpf.