Cytotoxicity assays with the rainbow trout R(1) cell line

For evaluation of the toxicity of aquatic pollutants, cultured fish cells are a potential alternative to fish bioassays. In this study, cells of the fibroblast-like R(1) cell line from rainbow trout (Oncorhynchus mykiss) were exposed to a total of 30 organic and inorganic chemicals, in order to reveal possible correlations between R(1) cytotoxicity and (a) toxicity to fish in vivo, (b) cytotoxicity data from other established fish cell lines, and (c) physicochemical parameters of the test agents. Cytotoxicity was assessed using the crystal violet (CV) staining technique, which determines the number of cells that are able to attach to the culture substratum during a 24-hr exposure period. For a broad spectrum of test compounds, including heavy metals as well as organic chemicals, there was good correlation of in vivo lethality and in vitro cytotoxicity (n = 21, r = 0.84). However, of 21 chemicals, six (HgCl(2), CuSO(4), 2,4-dichlorophenol, 4-chloroaniline, chlorobenzene and phenol), were toxic to fish at concentrations at least 10 times lower than those in the cytotoxicity assay, whereas the in vitro assay was found to be more sensitive than the in vivo test for one chemical only (trichloroacetic acid). R(1) midpoint toxicity values (CV(50)), on the other hand, closely agreed with cytotoxicity data reported for other fish cell lines (FHM, BF-2, GFS), both in absolute sensitivity and in relative ranking. For the 18 organic chemicals tested, a correlation between cytotoxicity in R(1) cells and their octanol/water partition coefficient could be established. In conclusion, the R(1) cell line seems to be a useful tool for screening studies in order to rank the toxicity of environmental pollutants or to evaluate structure-activity relationships.