Fig. 3
The endothelial efflux systems in Tg2576 mice are significantly hindered. a, Cross-sectional views of cortical vessels perfused with calcein-AM for 10 min under control conditions (left) and simultaneous inhibition of ABCC1 and ABCB1 transporters with 0.6 mM PRO and 1 µM ELA, respectively (right). Without blockers, no calcein accumulation was detected in endothelial cells (arrow heads, left), while it was observed after applying PEO and ELA (arrow heads, right). b, Dose-response curve showing the concentration-dependent accumulation of calcein 30 min after applying PRO or ELA. The ‘control’ datapoint denotes calcein accumulation in absence of both blockers. c, MIPs of capillaries recorded at 10 min demonstrating calcein accumulation under control conditions as well as inhibition of ABCC1, ABCB1 or both by 0.6 mM PRO, 1 µM ELA or a mixture of both, respectively, in WT mice (top row) and Tg2576 mice (bottom row). In WT mice capillaries, no calcein accumulation could be observed under control conditions, therefore the capillary’s lumen was manually outlined (dashed ROI) using simultaneously perfused TMR. Arrowheads denote extravascular autofluorescent aggregates in aged mice. d, Calcein accumulation in ECs at 10 min in absence of blockers in Tg2576 mice was significantly higher than that in WT mice (nROI WT mice = 5, nROI Tg2576 mice = 5, *P < 0.05). e, Quantification of calcein accumulating at 10 min in WT and Tg2576 mice in absence and presence of ABCC1 and ABCB1 blockers. A similar pattern of calcein accumulation was observed within both WT and Tg2576 mice groups. Compared to control conditions, applying PRO led to insignificant calcein accumulation, while applying ELA or ELA + PRO mixture resulted in significantly increased calcein accumulation. Data, presented as mean ± SEM, were obtained from 24 injections/6 animals (nROI = 5 for all groups, two-way ANOVA, *P < 0.05, ns; insignificant difference, see supplementary information for details). f, Inhibitor-induced increases in calcein fluorescence with respect to control (no blockers) conditions. PRO-sensitive ABC transporters were almost absent in Tg2576 mouse brains, while ELA-sensitive extrusion remained unchanged (multiple t-tests, *P < 0.05, ns; insignificant difference).