Fig. 5
Macrophage/microglial HO-1 is critical to ICV DFX neuroprotection and improvement in cognitive outcome after SAH—Cortical and hippocampal damage as well as cognitive outcome were measured after SAH induction and ICV DFX treatment in the following HO-1 conditional knockouts: Hmox1fl/fl, LyzMCre:Hmox1fl/fl, and NesCre:Hmox1fl/fl. a Representative confocal images of cortical and hippocampus sections for each genotype after SAH on POD7. Each color represents the following: green = HO-1; red = Iba-1/microglia; yellow = overlap of green and red/co-localization of HO-1 and microglia; blue = DAPI nuclei counterstain. All scale bars = 20 μm. b The percent quantification of co-localization per high-powered field for each genotype’s Z-stacked images. Co-localization percentage was obtained by dividing the total number of yellow-positive cells by the total number of DAPI-positive cells. LyzMCre:Hmox1fl/fl SAH mice showed the least HO-1/Iba-1 co-localization percentage in both the cortex and hippocampus as compared to Hmox1fl/fl and NesCre:Hmox1fl/fl SAH mice (two-way ANOVA P < 0.05; *P < 0.05; n = 4 per group). c TUNEL (red) stained images of cortical and hippocampal sections from each group with DAPI (blue) nuclei counterstain on POD7 (scale bar = 20 μm). d Quantification of TUNEL-positive cells from each treated genotype. Both Hmox1fl/fl and NesCre:Hmox1fl/fl SAH mice showed significantly less cortical and hippocampal damage than LyzMCre:Hmox1fl/fl SAH mice when treated with ICV DFX. (Two-way ANOVA P < 0.05; *P < 0.05 between groups for cortical damage and **P < 0.05 between groups for hippocampal damage; n = 4 per group). e Morris water maze testing of HO-1 conditional knockout cognition after SAH induction and ICV DFX treatment. Inset, bar graph of data for POD4, 5, and 7 shows both Hmox1fl/fl and NesCre:Hmox1fl/fl SAH mice performed significantly better than LyzMCre:Hmox1fl/fl SAH mice on POD5 and 7 when treated with ICV DFX, with a similar trend on POD4. (Two-way ANOVA P < 0.05;# P = 0.07 between groups on POD4; *P < 0.05 between groups on POD5 and 7; n = 4 per group)