Fig. 2

P-glycoprotein activity assay by measuring efflux of Rhodamine 123 (a P-gp probe) in BBB models at the ages of 3 months (n = 7 for WT and AD), 6 months (n = 4 for WT and AD), and 12 months (n = 8 for WT, n = 4 for AD). Abluminal fluorescence intensities of rhodamine 123 are expressed in percentage of control (n = 17) corresponding to a coated transwell without cells as indicated in methods