Fig. 8. Effect of in vivo caspase-3 inhibition on CA1 neuron survival and DNA fragmentation.A, Low-power fields (40×) showing representative cresyl violet staining (a, c, e) and TUNEL (b, d, f) in the hippocampus 3 d after sham operation (a,b), after ischemia plus vehicle infusion (c, d), or after ischemia plus caspase-3 inhibitor infusion (total dose, 4.5 μg; e, f).Arrows in c and e mark cell death in the CA1 sector. Arrows in dand f mark DNA-fragmented (TUNEL-positive) cells in the CA1 sector. B, High-power fields (400×) showing representative cresyl violet staining (a,c, e, g) and TUNEL counterstained with cresyl violet (b, d,f, h) in the CA1 sector. Three days after sham operation (a, b), no cell death or DNA fragmentation is present in CA1; 3 d after ischemia plus vehicle infusion (c, d), the majority of CA1 neurons show pyknotic changes (c) and TUNEL labeling (d); 3 d after ischemia plus caspase-3 inhibitor infusion (e,f), many neurons show normal morphology (yellow arrowheads), and decreased amounts of neurons show pyknotic changes (e) or TUNEL labeling (red arrowheads; f); and 7 d after ischemia plus inhibitor infusion (g, h), both survival neurons (yellow arrowheads) and TUNEL-positive cells (red arrowheads; h) are present in the CA1. Scale bar, 50 μm.