MAPT and Alzheimer disease: Histochemical analysis of brain slices demonstrated that PRO-Br at doses of 1.0 and 2.5 mg/kg significantly reduced AT8-positive cell count in the cortico-hippocampal regions in 3xTg-AD mice (Figures 4A,B), and AT8-, and PHF1-positive cell counts in P301S tau mice (Figures 4C–F).