Gill epithelial cells as tools for toxicity screening—comparison between primary cultures, cells in suspension and epithelia on filters

Abstract

In the search for suitable cell models that could be used in a test battery for toxicity screening purposes, we have focused on gill epithelial cells from rainbow trout. Gill epithelial cells are attractive models, since the gill is the primary target and uptake site for many toxicants in the water (Evans, D.H., 1987. Environ. Health Perspect. 71, 54–58). The aim of this study was to compare the sensitivity of gill epithelial cells in different test systems: suspensions, primary cultures and epithelia on filters in order to find out which system would be most suitable in a test battery for toxicity screening. The toxicity of the first 30 reference chemicals from the MEIC (multicenter evaluation of in vitro cytotoxicity) project (Bondesson, I., Ekwall, B., Hellberg, S. et al., 1989. Cell Biol. Toxicol. 5, 331–347) to gill epithelial cells in primary culture was tested using the fluorescent viability probe calcein-AM. Ten of the chemicals were also tested on cells suspended after 6–8 days in culture and five of the chemicals were tested on cells cultured on permeable filters. Decrease in transepithelial resistance was used as the endpoint for cells cultured on filters. The results were compared with toxicity data previously obtained by using freshly isolated gill epithelial cells in suspension. There was no significant difference in sensitivity of gill epithelial cells in suspension, primary cultures or resuspended cells. This observation strongly supports the use of cells in suspension in a test battery for toxicity screening purposes. Cultured epithelia on filters proved to be less suitable for screening purposes due to the considerable variation in resistance between epithelia even from the same fish.