Figure 1

Hyperphosphorylated pathological Tau (AT8) expression coincides with the loss of MAP2-IR in the human HD hippocampus. Hippocampal slide series from HD (n=5 cases/severity Grade) and age- and sex-matched CT (n=6) were studied. Immunofluorescent staining was carried out on serial paraffin-embedded hippocampal tissue sections (6 μm in thickness). Cresyl violet staining was used to count the number of neurons present in the GCL. (a–e) Representative images of triple immunofluorescent labeling (a and f) for MAP2⁺ neurons (in red) expressing phosphorylated Tau (AT8, in green) and DAPI (blue). Different morphologies of AT8⁺ cells, including ring-like perinuclear (b, c, white arrow), flame (d, red arrow) and globular inclusions (b, red arrowhead) as well as neuropil threads (e) can be seen in the GCL and hilus of a Grade 3 HD patient and as shown in the DG and hilus of an Alzheimer’s disease (AD) patient (f) for comparative purposes. (g–i) MAP2 and DAPI immunofluorescence in a CT (g), Grade 3 (h) and Grade 4 (i) HD case with quantification (j and k) revealing a stage-dependent neuronal decrease in the DG. This result was further confirmed using a quantification of cresyl violet-stained cells against a MAP2 labeling (k). Statistical analysis was performed by one-way analysis of variance with Newman–Keuls Multiple Comparison posthoc test. Statistical differences (mean±S.D.) in panels (j and k) *P<0.05 versus CT; **P<0.01 versus CT. Scale bars in panels (a–e), (g–i)=50 μm, (f)=25 μm