Survival of neuronal cells and deposition of Aβ peptides.

Brains were collected from subset groups, and histological changes were determined as described in the Materials and Methods. (A) Slide bearing sections of brain tissue were stained with Nissl and observed at 40× or 200× magnification. The total number of neuronal cells was calculated per 80 mm2. (B) The accumulation of Aβ peptides in the brains of Tg mice were detected by immunohistochemical staining using specific antibody for total Aβ peptide, and their structures were observed at 400× magnification. A total of 5–6 mice were assayed per group, in triplicate, by immune staining. (C) Concentration of soluble Aβ-42 peptide was detected in brains of Tg2576 mice by slot blot analysis. (D) To test an impairment of learning and memory in the Morris water maze, the first reaching time was evaluated in the target quadrant of the pool among NT and Tg mice. (E) To detect the hippocampal neuron loss in the Tg mice, the number of neuronal cells were counted in brain sections stained with anti-APP antibodies. Data are reported as the mean ± SD. *, p<0.05 compared to the NT group.