Cytotoxicity and apoptosis induced by fumonisin B1, beauvericin and ochratoxin A in porcine kidney PK15 cells:: effects of individual and combined treatment

The objective of this study was to determine individual and combined effects of fumonisin B-1 (FB1), beauvericin (BEA) and ochratoxin A (OTA) on porcine kidney epithelial PK15 cell survival by measuring lactate dehydrogenase (LDH) activity, apoptotic index and caspase-3 activity. Cells were treated with 0.05, 0.5 and 5 mu g/ml of each mycotoxin or with the combinations of two or all three mycotoxins for 24 and 48 h. Changes in LDH and caspase-3 activity, and in apoptotic index showed that the cytotoxic and apoptotic effects of these mycotoxins were concentration- and time- dependent. Significant increase of LDH activity was observed after 48 h of exposure to the highest concentration of FB1 (45%), BEA (84%) and OTA (77%), as compared to control. OTA increased caspase-3 activity after 24 h of treatment with 0.5 mu g/mL (84%), while BEA (319%) and FB1 (419%) significantly affected this enzyme activity after 48 h (P < 0.05). Increase of caspase-3 activity preceded significant morphological apoptotic changes, which were detected after 48 h of exposure to a single toxin. Combined treatment with FB1, BEA and OTA resulted mostly in additive effects on LDH activity, and additive and synergistic effects on caspase-3 activity and apoptotic index.