CYTOTOXICITY INDUCED BY NIVALENOL, DEOXYNIVALENOL, AND FUMONISIN B1 IN THE SF-9 INSECT CELL LINE

The toxicity of the mycotoxins nivalenol (NIV), deoxynivalenol (DON), and fumonisin B1 (FB1) was studied in the lepidopteran Spodoptera frugiperda (SF-9) cells, by the trypan blue dye-exclusion and 3-(4,5-dimethylthiozole-2-yl)-2,5-biphenyl tetrazolium bromide (MTT) tests, uptake analyses of cytotoxicity, and cell metabolism, respectively. Deoxytribonucleic acid analysis by flow cytometry was used to identify apoptosis and cell cycle distribution. After 48 h of exposure, the MTT and trypan blue dye-exclusion tests indicated that NIV was significantly more toxic than DON, and both were significantly more toxic than FB1. The IC50 (mycotoxin concentration resulting in 50% inhibition of proliferation) values for NIV and DON were 4.5 and 41 μM, and the CC50 (mycotoxin concentration that caused 50% cytotoxicity) values were 9.5 and 45 μM, respectively. At the highest concentration of FB1 (100 μM), there was 80% viability. With the same incubation time, cell cycles distribution showed an arrest of cells in the G0/G1 phase in the presence of NIV (up to 0.3 μM), DON (up to 3 μM), and FB1 (up to 10 μM). Morphological evidence of apoptosis was related to the toxicity of the substances in that the more toxic NIV induced late apoptosis, whereas DON and FB1 produced less-severe morphological changes characteristic of early apoptosis. This study suggests that NIV is more toxic than DON, which in turn is more toxic than FB1. These mycotoxins can modify the normal progression of the cell cycle and induce an apoptotic process.