Rapid detection of Aβ deposits in APP transgenic mice by Hoechst 33342

The accumulation of beta-amyloid (A beta) is the earliest event seen in the neocortex and hippocampus of Alzheimer's disease (AD) patients. Transgenic mouse models of A beta deposition are excellent tools for validating pharmacological therapies for reducing A beta burden. Sensitive and rapid probes should be needed for detecting A beta 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 A beta plaques in AD brains, does not visualize A beta 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 A beta plaques in APP Tg Mouse. These findings could allow us to rapidly detect A beta plaques in AD mouse models, and to develop improved compounds for detecting A beta plaques in vivo in mouse models. (C) 2008 Elsevier Ireland Ltd. All rights reserved.