Scanning electron microscopic observation of the repair of rat bladder urothelium damaged by Adriamycin.

Abstract

The changes which occurred in the bladder urothelium were observed with the use of a SEM after 1 m/ of saline solution of Adriamycin (2 mg/m/) was kept in the bladder of a Wistar rat for 30 minutes.The normal superficial cells of the bladder urothelium were large , flattened surface cells and had a mature surface pattern. They were damaged by Adriamycin and desquamated.The cells of the intermediate layer, which were forced to line the luminal surface of the bladder due to loss of the superficial cells, were smaller in size and had an immature surface pattern. This immature surface pattern of the cells changed and took on an aspect remniscent of the normal superficial cells within 6 hours afterinstillation of Adriamycin, though the size of the cells remained small. Within 12 hours, the mitotic figures were observed in the cells of the basal layer in the light microscopic sections. Four weeks after instillation of Adriamycin, there were differences neither in the surface pattern nor in cell-size between the renewed superficial cells and the normal superficial cells. From these findings, it was suggested that the damaged bladder urothelium repaired firstly its urine-tissue fluidbarrier function and then replenished itself with the urothelial cells. The cell replacement mechanisms in the urothelium were also discussed.