Fig. 4

Prnp deletion reverses DKI-dependent loss of synaptic immunohistochemical markers. A Representative images of staining for the pre-synaptic marker SV2A from the dentate gyrus of 10-month-old WT, Prnp^−/−, DKI and DKI; Prnp^−/− mice. Scale bar = 20 μm. B Quantification of SV2A immunoreactive area in the dentate gyrus demonstrates a significant decrease in synapse density in DKI mice that is not observed in DKI; Prnp^−/− mice. Data are graphed as mean ± SEM, analyzed by ordinary one-way ANOVA with Dunnett’s multiple comparisons test to DKI, *P < 0.05, **P < 0.01, n = 18 for WT, n = 20 for Prnp^−/−, n = 21 for DKI, and n = 23 for DKI; Prnp^−/−. C Representative images of staining for the post-synaptic marker PSD-95 from the dentate gyrus of 10-month-old old WT, Prnp^−/−, DKI and DKI; Prnp^−/− mice. Scale bar = 20 μm. D Quantification of PSD-95 immunoreactive area in the dentate gyrus demonstrates a trend (P = 0.09) towards greater area in DKI; Prnp^−/− mice compared to DKI mice. Data are graphed as mean ± SEM, analyzed by ordinary one-way ANOVA with Dunnett’s multiple comparisons test to DKI, n = 16 for WT, n = 19 for Prnp^−/−, n = 20 for DKI, and n = 23 for DKI; Prnp^−/−