Fig. 8.

a Serial cryostat sections (8 μm thickness) after staining with hematoxylin of gingival epithelium (blue) invaded by stromal papillae (green) containing ascending and descending limbs of a capillary loop (pink) after the BABB clearing procedure. b Stacks of sections of stromal papillae prepared based on the images in (a; A). Epithelium is shown as in Sect. 1. One papilla is sectioned from the top toward the bottom (upper papilla), and the other is sectioned halfway to the bottom. c Low-magnification 2D projection of a 3D image prepared with the use of light sheet microscopy of human gingiva embedded in agarose with the endothelium of blood vessels immunohistochemically stained using anti-CD31 antibodies conjugated with Alexa Fluor 568 (red) and nuclear staining using YOYO-3 (blue). Note that pseudocolors are used to optimize contrast. Detailed image bar of a capillary loop (red) in a connective tissue papilla that is invading into the epithelium of human gingiva in the box was taken from the 3D image. Bar = 20 µm. d Light microscopy images of cryostat sections of the gingival sample stained with PAS. e, f Giemsa staining regions marked with E, S, and SP on (e, f) are staining of the epithelium (E), stroma (S), and stromal papillae (SP) containing capillaries. Bars = 50 µm (d, e) and 25 µm (f). All images were reproduced with permission from Ref. [58]. (Color figure online)