Cytotoxicity of four trichothecenes evaluated by three colorimetric bioassays.

The application of cell culture technique for screening of low concentrations of Fusarium mycotoxins was examined. Three colorimetric bioassays were used to determine the cytotoxicity of the trichothecenes T-2 toxin (T-2), HT-2 toxin (HT-2), deoxynivalenol (DON) and nivalenol (NIV) to 3T3 mouse fibroblasts (3T3 cells). The bioassays assess DNA synthesis (incorporation of 5-bromo-2'-deoxyuridine; BrdU), metabolic activity (cleavage of 3-(4,5-dimethyltiazol-2-yl)-2,5-diphenyltetrazolium bromide; MTT) and cell membrane damage (release of lactate dehydrogenase; LDH), respectively. The BrdU bioassay was the most sensitive and the IC50 values (50% response compared to untreated cells) of T-2, HT-2, DON and NIV were 4.6, 13, 263 and 365 ng/ml, respectively. At the same toxin concentrations used in the BrdU bioassay, only T-2 and HT-2 were toxic enough to obtain IC50 values using the MTT bioassay. The IC50 values for T-2 and HT-2 were 12 and 68 ng/ml, respectively. When determined by the LDH bioassay, the IC50 values of T-2 and HT-2 were 18 and 42 ng/ml, respectively. At the tested concentrations, DON and NIV had a minor effect on the 3T3 cells when evaluated by the MTT and LDH bioassays. The BrdU bioassay in combination with 3T3 cells was found to be a suitable method for determination of trichothecene-induced toxicity at low concentrations.