Comparison of four different colorimetric and fluorometric cytotoxicity assays in a zebrafish liver cell line

Abstract

A broad spectrum of cytotoxicity assays is currently used in the fields of (eco)toxicology and pharmacology. To choose an appropriate assay, different parameters like test compounds, detection mechanism, specificity, and sensitivity have to be considered. Furthermore, tissue or cell line can influence test performance. For zebrafish (Danio rerio), as emerging model organism, cell lines are now increasingly used, but few studies examined cytotoxicity in these cell systems. Therefore, we compared four cytotoxicity assays in the zebrafish liver cell line, ZFL, to test four differently acting model compounds. The tests comprised two colorimetric assays (MTT assay using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide, and the LDH assay detecting lactate dehydrogenase activity) and two fluorometric assays (alamarBlue® using resazurin, and CFDA-AM based on 5-carboxyfluorescein diacetate acetoxymethyl ester). Model compounds were the pharmaceutical Tamoxifen, its metabolite 4-Hydroxy-Tamoxifen, the fungicide Flusilazole and the polycyclic aromatic hydrocarbon Benzo[a]pyrene.