AAV-mVEGF-C promotes drainage of CSF-injected Gd-DOTA into dCLNs. (A) Outline of the experimental procedure. 8-wk-old mice were analyzed by DCE-MRI after a prior ICM injection of either AAV-mVEGF-C or AAV-CTRL at 4 wk old (n = 10/group). (B) T1 mapping (1–1,700 ms range) was performed 1 h after intra-CSF Gd-DOTA administration. Each dot represents one mouse. Note the comparable voxel number between the two groups of mice (P = 0.65, Unpaired t test; P = 0.853, Mann–Whitney U test). (C) T1 mapping of extracranial Gd-DOTA efflux in the cribriform plate–olfactory epithelium area. Each dot represents one mouse (P = 0.30, Unpaired t test; P = 0.280, Mann–Whitney U test). (D) Plane sagittal view of the brain at the level of the dCLNs showing the T1 signal mapped to the node (white arrows) and an enlarged dCLN in the AAV-mVEGF-C mouse compared with CTRL. Note that the nodal volume and the intra-nodal content of Gd-DOTA were both increased in VEGF-C preconditioned mice compared with controls. (E) Measurement of dCLN volume through anatomical MRIs (AAV-mVEGF-C: 115.2 ± 12.1 voxels and AAV-CTRL: 56.5 ± 3.7 voxels, n = 20 CLNs/group, ****P < 0.0001, Mann–Whitney test). (F) Linear regression analysis of data in E (AAV-mVEGF-C: R² = 0.89 P < 0.0001; AAV-control: R² = 0.39 P < 0.004, linear regression model. (G) Postmortem analysis of dCLN weight (AAV-mVEGF-C [mg]: 0.19 ± 0.02 and AAV-CTRL [mg]: 0.11 ± 0.01, *P < 0.03, Unpaired t test, n = 9 dCLNs/group). (H and I) Quantification of ICM-injected fluorescent OVA-A⁶⁴⁷ in dCLNs and sCLNs at indicated timepoints 4 wk (H) and 2 wk (I) after AAV administration (n = 4–9/group, *P < 0.05, Mann–Whitney test). Data are represented as mean ± SEM. Scale bar: 1.5 mm (B–D). w, week.