Cell-specific Cu/Zn SOD expression in the late excitotoxicaly lesioned immature brain. One day after the lesion (A), neuronal bodies were condensed in the lesioned zone (*) when compared to the penumbra zone (Pen). Moreover, the lesion core (*) showed very low or no expression of Cu/Zn SOD. In contrast, 3 days after injection, cortical expression of Cu/Zn SOD increased in the whole lesion (B, *). Neurons in the penumbra (B, Pen) and reactive hypertrophic astrocytes (C) within the degenerative core (*) expressed Cu/Zn SOD after 3 days. These GFAP-positive hypertrophic astrocytes were the main cell type expressing Cu/Zn SOD in the lesion core (D). This pattern of expression was maintained until 7 days post-lesion (the last time analyzed), when the glial scar was evident. Scale bars in A-D: 20 μm.