In the vehicle + TFI group, TNF-α immunoreactivity in the CA1 pyramidal cells was dramatically increased (252.0% of the sham group) in the pyramidal cells at 2 days post-ischemia (Figure 4Ab,C), and, at 5 days post-ischemia, TNF-α immunoreactivity in the CA1 pyramidal cells was hardly shown because the pyramidal cells were dead at this time: in these pyramidal cells, relative immunoreactivity (RI) was 25.1% of the sham group (Figure 4Ac,C). This evidence concerns the gene TNF and ischemia.