Fig. 2. Scavenging ONOO^– with 2 µM FeTMPyP or 10 µM FeTPPS protects against KA-mediated excitotoxicity and oxidative stress. (A) Wild-type and wild-type mice infused with either 2 µM FeTMPyP or 10 µM FeTPPS were injected with KA and sacrificed at day 5 (left). tPA^–/– mice were infused with 2 µM FeTMPyP prior to injection with KA with or without co-injection of 5 µg/µl tPA (right). Sections were stained with Cresyl Violet to assess neuronal survival. Bars, 50 µm. (B) To quantify the injury-derived oxidative stress, mice were injected with 1 mg/ml DHE intraperitoneally 2 hours prior to sacrifice. Wild-type mice and tPA^–/– mice injected with tPA, but not tPA^–/– mice, FeTMPyP- or FeTPPS-treated mice, exhibit increased DHE oxidation in CA1 and CA3. Fluorescent images were converted to pseudocolor using the Scion software. A scale for quantitation is shown on the side. (C) Quantification of neuronal survival was performed as described in the Materials and Methods. Statistical analysis was performed using a two-tailed t test as compared with wild-type KA-treated mice. **P<0.01. There was no significant difference between FeTMPyP, FeTPPS and tPA^–/– mice. (D) Quantification of fluorescence was determined using Scion Image and represents fluorescent intensity of the injected side after subtracting the background of the uninjected side. Statistical analysis using one-way ANOVA followed by a Bonferroni-Dunn test for multiple comparisons was used to compare fluorescent intensities between groups of the CA1 and CA3 subregions of the hippocampus. ***P<0.001 indicates significant increase in fluorescent intensity; n.s. indicates no significance between groups. n=6 per treatment group.