Fig. 4

Caspase-inhibited neurons display chromatin degradation. Neurons were incubated with colchicine (1 µM) in the presence or absence of N-benzyloxycarbonyl-Val-Ala-aspartyl-fluoromethyl ketone (zVAD-fmk; 100 µM) or with zVAD-fmk alone. After different time points, the percentage of neurons retaining plasma membrane integrity was determined by counting calcein acetoxymethyl ester (calcein-AM)-positive cells. Then, DNA fragmentation was analyzed by field-inversion gel electrophoresis. The arrow indicates high molecular weight DNA fragments of 50 kbp.