Description:
<p>The toxicity of the mycotoxins nivalenol (NIV), deoxynivalenol (DON), and fumonisin<tex-math>$B_1 (FB_1)$</tex-math>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. Deoxyribonucleic 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 FB<sub>1</sub>. The IC<sub>50</sub>(mycotoxin concentration resulting in 50% inhibition of proliferation) values for NIV and DON were<tex-math>$4.5 and 41 \muM$</tex-math>, and the<tex-math>$CC_{50}$</tex-math>(mycotoxin concentration that caused 50% cytotoxicity) values were<tex-math>$9.5 and 45 \muM$</tex-math>, respectively. At the highest concentration of<tex-math>$FB_1 (100 \muM)$</tex-math>, there was 80% viability. With the same incubation time, cell cycle distribution showed an arrest of cells in the G<sub>0</sub>/G<sub>1</sub>phase in the presence of NIV (up to<tex-math>$0.3 \muM$</tex-math>), DON (up to<tex-math>$3 \muM$</tex-math>), and FB<sub>1</sub>(up to<tex-math>$10 \muM$</tex-math>). Morphological evidence of apoptosis was related to the toxicity of the substances in that the more toxic NIV induced late apoptosis, whereas DON and FB<sub>1</sub>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 FB<sub>1</sub>. These mycotoxins can modify the normal progression of the cell cycle and induce an apoptotic process.</p>