FIGURE 6.

Perineuronal networks (PNN) decrease in KCC2 KO^PV mice. (A) Representative WFA stainings of the somatosensory cortex of a WT^PV mouse at the age of 8 weeks. Scale bar 5 μm. (B) Representative WFA stainings of the hippocampus (left), the S1 (middle) and RSP cortex (right) of WT^PV and KCC2 KO^PV mice at 23 weeks of age. Scale bars 100 μm. (C) Quantification of WFA⁺/tdTomato cells in the hippocampus (left), S1 (middle), and RSP (right) cortex of WT^PV and KCC2 KO^PV mice at the age of 8 and 23 weeks shows a reduced proportion of ensheathed PV-INs in older KO^PV mice (n = 15/15 slices, N = 5/5 mice; 1-way ANOVA; Bonferroni’s multiple comparison test; ns not significant; ***p < 0.001). (D,E) WFA signal intensity per individual cell in the hippocampus (D) (n = 12/9 slices; N = 4/3 mice; 1-way ANOVA; Bonferroni post-test; ns not significant; ***p < 0.0001). WFA signal intensity per 0.1 mm² in the S1 cortex (left) and RSP (right) decreases over time in KCC2 KO^PV mice (n = 13/15 slices; N = 5/5 mice; 1-way ANOVA Bonferroni post-test; ns not significant; ***p < 0.0001). (F) Representative GFAP staining of the cortex and hippocampus of WT^PV and KCC2 KO^PV at the age of 23 weeks. Scale bar 100 μm. (G) Close up of GFAP -stained reactive astrocytes in CA3 in KCC2 KO^PV. Scale bar 50 μm.