Figure 5.

Attenuated microglial activation in Fosb-null hippocampus 24 h after kainate administration. A. Detection of activated microglia in hippocampal CA3 region 24 h after kainate injection. Coronal sections prepared from wild-type (WT) and Fosb-null (Null) mouse brains were subjected to laser scanning confocal immunofluorescence microscopy with anti-CD68 and anti-Iba-1 antibodies. Nuclei were counter-stained with DAPI. Top panels: Merged z-staked images of samples 24 h after saline injection. Bottom panels: Merged z-stacked images of samples 24 h after kainate injection. Blue, DAPI; green, CD68; red, Iba-1. Scale bars = 100 μm. B. Higher magnification images of Figure 5A. Scale bars = 50 μm. C. The percentages of double CD68 and Iba-1 positive cells in Fosb-null (Null) CA3 regions 24 h after kainate administration compared with those in wild-type (WT). Level 0 (Lv. 0); completely CD68-negative cells, Level 1 (Lv. 1); exhibiting less than six CD68-positive dots in a single cell body, Level 2 (Lv. 2); carrying more than five CD68-positive dots or homogeneous immunoreactivity in a cell body. One way ANOVA (F_3,8 = 26.35 , p = 0.0002 (Lv.2), F_3,8 = 25.01, p = 0.0002 (Lv.1), * p = 0.0002, ** p = 0.003, # p = 0.0003, ## p = 0.0021, Tukey-Kramer HSD post hoc comparison). D. Microglial cell body areas in Fosb-null (Null) CA3 regions 24 h after kainate administration compared with those in wild-type (WT). One way ANOVA (F_3,716 = 274.38, p < 0.0001, * p < 0.0001, Tukey-Kramer HSD post hoc comparison). E. Number of microglial processes in Fosb-null (Null) CA3 regions 24 h after kainate administration, compared with those in wild-type (WT). One way ANOVA (F_3,716 = 64.96, p < 0.0001, * p < 0.0001, Tukey-Kramer HSD post hoc comparison). F. Thickness of microglial processes in Fosb-null CA3 regions 24 h after kainate administration compared with those in wild-type (WT). One way ANOVA (F_3,716 = 91.61, p < 0.0001, * p < 0.0001, Tukey-Kramer HSD post hoc comparison). G. Reduced expression of Il1b, Il6, and Tnf mRNAs in Fosb-null (Null) hippocampus 24 h after kainate administration, compared with wild-type (WT). Saline, 24 h after saline injection; KA, 24 h after kainate injection. Relative expression levels were estimated using the expression level in wild-type treated with saline as a control. One way ANOVA [F_3,8 = 10.98, p = 0.0033, * p = 0.0426, Hsu’s multiple comparisons with best (MCB)]. One way ANOVA (F_3,8 = 31.50, p < 0.0001, # p = 0.0025, Tukey-Kramer HSD post hoc comparison). Error bars show mean ± SEM. To quantify expression level of each mRNA, total RNA was reverse-transcribed to cDNA and used for qPCR analysis using appropriate primer sets (Table 1).