Fig. 7

CSF tracer distribution within the choroid plexus. A Representative histology of large CSF tracer distribution in the lateral ventricle (LV), anterior third ventricle (3V), and posterior 3V choroid plexuses (ChP) 4 h post-15-nm gold nanoparticle (AuNP) injection into the right LV of P7 rodents. Black dotted line indicates the apical surface of ChP epithelial cells, white dotted line indicates the basolateral surface of ChP epithelial cells. Scalebars = 25 µm. B–D Quantification of 15-nm AuNP integrated density along the luminal and apical surfaces of the LV (B), anterior 3V (C), and posterior 3V (D) ChP. 15-nm AuNPs distributed along the apical surface of the anterior and posterior 3V ChP significantly more than the luminal surface. Data are mean ± SD, n = 3 per group; Unpaired two-tailed t test. E–F Quantification of 15-nm AuNP distribution in the LV, anterior 3V, and posterior 3V ChP along the luminal (E) and apical (F) surfaces. There was significantly more 15-nm AuNP distribution on both the luminal and apical surfaces of the posterior 3 V ChP compared to the anterior 3V ChP (F). Data are mean ± SD, n = 3 per group; One-way ANOVA with post-hoc Tukey. All data are representative of 3 rodents. G Representative photomicrographs of small CSF tracer (brown) distribution in the LV, 3V, and fourth ventricle (4V) ChP 10 min post-1.9-nm gold nanoparticle AuNP injection into the lateral ventricle in P7 rodents. Black dotted line indicates the apical surface of ChP epithelial cells, white dotted line indicates the basolateral surface of ChP epithelial cells. Scalebars = 25 µm. H–J Quantification of 1.9-nm AuNP integrated density between the luminal and apical surfaces of the LV (H), 3V (I), and 4V (J) ChP. There was significantly more AuNP distribution along the luminal surface of the 3V and 4V ChP compared to the apical surface. Data are mean ± SD, n = 3 per group; Unpaired two-tailed t test. K, L Quantification and comparison of 1.9-nm AuNP distribution between the LV, 3V, and 4V ChP along the luminal (K) and apical surfaces (L). There was significantly more 1.9-nm AuNP distribution throughout the luminal 3V and 4V ChP compared to the LV, but no differences between regions on the apical ChP. Data are mean ± SD, n = 3 per group; One-way ANOVA with post-hoc Tukey. All data are representative of 3 rodents