Fig. 5

Compensatory hippocampal parvalbumin remodeling in TgF344-AD rats. We hypothesized that the hippocampal PVB network would undergo neuroplastic reorganization in TgF344-AD rats, coinciding with GABAergic compensation. We assessed PVB (green) staining in 9-, 12- and 15-month-old NTg and Tg rats (representative images from n = 6 rats/genotype at each age). At 9 months, compared to NTgs (a), Tg (b) rats exhibited increased PVB staining, with greater complexity of processes. c, d At 12 months of age, the overall PVB staining density was decreased; however, the Tg (d) rats exhibited increased complexity in the DG. e, f At 15 months of age, there was a robust loss of PVB staining density and complexity in Tg rats throughout the hippocampus, compared to NTg rats and compared to younger ages. g Quantification of dendritic length from CA1 PVB neuronal traces showed significantly longer dendrites in Tg rats at 9 months, no differences at 12 months, and a loss at 15 months of age, compared to NTgs. h In the DG, Tg PVB neurons exhibited significantly increased dendritic length at 9 and 12 months of age and reduced dendritic length at 15 months compared to NTgs. Scale bars, 200 μm (whole hippocampus) and 50 μm (CA1/DG). Data are mean ± SEM (from n = 16 cells/cohort, sampled across 4 rats/genotype at each age); two-way ANOVA with correction for multiple comparisons with a Holm-Sidak post hoc test; **P < 0.01