Rapid detection of Abeta deposits in APP transgenic mice by Hoechst 33342.

The accumulation of beta-amyloid (Abeta) is the earliest event seen in the neocortex and hippocampus of Alzheimer's disease (AD) patients. Transgenic mouse models of Abeta deposition are excellent tools for validating pharmacological therapies for reducing Abeta burden. Sensitive and rapid probes should be needed for detecting Abeta plaques ex vivo and in vivo in the transgenic mouse models. However, a thioflavin derivative, Pittsburgh Compound-B (PIB), which is a successful PET tracer for detecting Abeta plaques in AD brains, does not visualize Abeta plaques in APP and PS1/APP transgenic mice. Here, we report that Hoechst 33342, a cell-permeable fluorescent probe for staining DNA and nuclei, also detects Abeta plaques in APP Tg mouse. These findings could allow us to rapidly detect Abeta plaques in AD mouse models, and to develop improved compounds for detecting Abeta plaques in vivo in mouse models.