Cytotoxicity of chlorophenols to goldfish GFS cells with the MTT and LDH assays

The cytotoxicity of phenol and 14 chlorophenols (CPs) were examined in goldfish scale (GFS) cells, a fibroblastic cell line derived from goldfish scales. MTT reduction and intracellular LDH activities were examined as cytotoxicity indicators. Cell densities at inoculation were 1.0 x 10(5) cells/ml in the MTT assay and 0.5 x 10(5) or 0.1 x 10(5) cells/ml in the LDH assay. No change in the midpoint cytotoxicity concentration (IC(50)) was observed in either assay at the same order of cell density (0.5-1.0 x 10(5) cells/ml). However, at low chemical concentrations, the LDH assay was more sensitive than the MTT assay. In addition, for many CPs, the LDH assay at 0.1 x 10(5) cells/ml was more sensitive than the MTT and LDH assays at the higher cell density levels. The correlation coefficients (r) for all IC(50) determinations were greater than 0.97. Good correlations between these assays and the neutral red (NR) assay were also observed (r > 0.97). The 1-octanol/water partition coefficient (log P) gave good correlation coefficients (r > 0.90) with IC(50) values of both the MTT and LDH assays in simple linear regression analyses. The study demonstrates that both the MTT and LDH cytotoxicity assays with GFS cells, together with the NR assay, can be applied to screen the acute toxicities of chemicals.