Gill epithelial cells as in vitro models in aquatic toxicology

Gill epithelial cells are less sensitive than fish for most test chemicals, but a high correlation and a slope of the regression line close to 1 suppo rt the use of gill epithelial cells for prediction of acute toxicity in fis h. Cells in suspension perform as well as cultured cells in the toxicity te sts. However, the use of cells in suspension results in a quicker and more cost-effective assay for toxicity screening, but the cells should be used w ithin about 5 hours of isolation. If a longer incubation time is required, cultured cells should be used. Cultured cells re-establish their polarity a nd contacts with other cells, and retain detectable amounts of enzymes for xenobiotic metabolism for at least 12 days in culture. Epithelial cell laye rs grown on filters seem to be less suitable for toxicity screening.