The expression of cleaved-caspase-3, 8 and number of cleaved-caspase-9-positive cells (% of DAPI+ cells) were dramatically increased in the MCAO group compared with sham group, suggesting that both intrinsic and extrinsic apoptosis were trigged in cerebral ischemia (Figures 2A,C–E-a5,b5,H; n = 4, P < 0.01). Here, CASP9 is linked to brain ischemia.