Neuronal Deletion of Caspase 8 Protects against Brain Injury in Mouse Models of Controlled Cortical Impact and Kainic Acid-Induced Excitotoxicity
(A) Mouse survival was monitored for 24 hours after exposure of control (n = 8) and Ncasp8−/− mice (n = 11) to KA. Non-linear x-axis corresponds to time following KA injection. (B) Seizure scores for control and Ncasp8−/− mice were determined every 15 min for 2 h and at longer intervals thereafter  . Percentage of TUNEL-positive neurons (C) and density of degenerating neurons (Masson's trichrome stain) (D) were assessed in the hippocampi of the control and Ncasp8−/− mice (mean±SEM). P values result from Student's t-test (B: *p = 0.008; C: *p = 0.002; D: *p = 0.005). Colorimetric intensity measurements were applied to Masson's trichrome-stained control (E) and Ncasp8−/− (F) hippocampi to obtain density of degenerating neurons in the annotated area (mark-up images). Arrows indicate hippocampal CA3–CA4 sectors and the hilus (E) and the CA3 sector (F). Apoptotic neurons were visualized by TUNEL assay (G, H), and cleaved-caspase 3 immunostaining (I–K) as presented on virtual (I, K) and mark-up (G, H, J) images of the hippocampal regions of the control (G, I, J) and Ncasp8−/− (H, K) mice. Brown color (DAB) on digital images and red, orange and yellow pixels on mark-up images denote positive staining. The arrow indicates TUNEL positive neurons in the CA3–CA4 sector.