Cell death in immature mouse brain following periventricular blood injection.A - Activated caspase 3 immunoreactivity is extremely rare in the SVZ of control mice (brown stained cells; hematoxylin counterstain) (arrow; this example is wild type). B – Following blood injection, activated caspase 3 immunoreactivity is prominent in the striatum (arrow) but very rare in the SVZ (this example is a PAR1 knockout). C – Quantitative analysis shows a statistically significant increase in caspase 3 immunoreactive cells in the striatum of most groups in comparison to intact control (p < 0.007), but there were no significant differences between the blood-injected groups (all p > 0.15; Wilcoxon method). All micrographs were taken at 400× magnification. Bar = 100 μm.