Figure 11.

Postnatal urothelial cell desquamation. (A) Cytokeratin 20 (CK20)-positive superficial cells (red, immunolabeled by antibodies against CK20) and CK20-negative intermediate cells (green, immunolabeled by antibodies against β-tubulin) desquamated in the lumen of the urinary bladder. In certain areas of the urothelium, superficial cells are still attached to the urothelium (arrows), whereas other areas of the urothelium are already peeled off, owing to cell desquamation (arrowheads). Detail in the frame is enlarged in B. Nuclei are stained with DAPI. Tissue section on postnatal day 10. L, lumen of the urinary bladder. (B) Enlarged detail of A shows desquamation of superficial cells (red fluorescence) and occasional underlying cells (green fluorescence) in the lumen (L) of the urinary bladder. Nuclei are stained with DAPI. (C) SEM image shows desquamated area of the urothelium. At the edge of this area, some desquamating cells are partly still attached to the urothelium. Postnatal day 8. (D) Immunostaining of CK20 (green fluorescence) shows intact luminal urothelial surface on the right and desquamated area with no superficial cells on the left side of the figure. Bird’s-eye view of the luminal urothelial surface of the tissue piece. Postnatal day 10. Nuclei are stained with DAPI. Bars: A = 100 μm; B–D = 10 μm.