Selective staining of the superficial cells of mouse urinary bladder epithelium by horseradish peroxidase (HRP).

A simple method for staining the superficial cells of mouse urinary bladder epithelium with horseradish peroxidase (HRP) is presented. HRP solution was instilled into the bladder lumen in vivo. After fixation with glutaraldehyde, the bladder was treated with Triton X-100 and then reacted with diaminobenzidine (DAB). Intense DAB reactions were detected throughout the whole of the cytoplasm of superficial cells by both light and electron microscopy. No reaction was observed in intermediate or basal epithelial cells. This simple method will be useful for the three-dimensional reconstruction of cell shape and identification of the stratification of transitional epithelial cell layers.