Fig. 3.

OTA induced apoptosis in SH-SY5Y cells and primary neurons by caspase activation. A OTA induced DNA fragmentation in SH-SY5Y cells. Cells were exposed to increasing OTA concentrations for 48 h, lyophilized apoptotic U937 cells were taken as positive control. B OTA induced caspase-9 and caspase-3 activation both in SH-SY5Y cells and primary neurons after 24 h incubation. Caspase-9 and caspase-3 were determined by Western Blot analysis. Densitometric ratio of caspase-9 and caspase-3 to β-actin was calculated; nd = non-detectable). C, D Caspase inhibitors Z-VAD-fmk and Z-DEVD-fmk partly attenuated OTA induced cell death. Z-VAD-fmk and Z-DEVD-fmk were pre-cultured with SH-SY5Y and primary neurons for 24 h, followed by another 24 h incubation with OTA. Cell viability was then determined by the neutral red assay. *P < 0.05; **P < 0.01 versus control (without Z-VAD-fmk or Z-DEVD-fmk, n = 4–5)