Figure 6.

rAAV1-IFNγ-injected 3×Tg-AD mice exhibit evidence of heightened neurogenesis within the transduced CA1 subregion of the hippocampus. Two-month-old 3×Tg-AD mice (N = 4 to 5 per experimental group) were stereotactically infused bilaterally twice with 2 μl (∼3 × 10⁹ transducing particles) of rAAV1-eGFP (A, D, G, J, and L) or rAAV1-IFNγ (B, E, H, K, and M). Mice received daily intraperitoneal injections of BrdU (50 mg/kg) for 3 days at 35 days after rAAV vector injection and were sacrificed 2 days after the final BrdU injection. A and B: diaminobenzidine immunohistochemical analysis for cells staining positive for BrdU incorporation was performed. C: The average numbers of BrdU-positive cells per microscopic field were quantified in the CA1 and dentate gyrus (DG) of the hippocampus and are presented in histogram format. Error bars indicate SEM. ***P < 0.001. Sections were co-incubated with a primary antibody specific for cell markers (red signal) for mature neurons (NeuN; D and E), neuronal progenitors (DCX; G and H), astrocytes (GFAP; J and K), or microglia (IBA-1; L and M), and a primary antibody for BrdU (blue signal). After incubation with a designated set of secondary antibodies, photomicrographs of the transduced CA1 subregion of the hippocampal formation were captured by two-color confocal microscopy. Overlapping signals appear pink. Insets in B, E, H, K, and M represent digitally magnified images of the respective outlined region in each photomicrograph for better visualization of stained cell morphology. Scale bars in A and L = 200 μm. Quantitative image analyses for cells costaining positive for NeuN and BrdU (F) and DCX and BrdU (I) were performed on each brain and presented in histogram format. Error bars indicate SEM. **P < 0.01.