THE ROLE OF MECHANICAL STIMULI IN RAT BLADDER CARCINOGENESIS

Regenerative Hyperplasia of Rat Urinary Bladder Urothelium after Transurethral Fulgulation

Abstract

Urothelial regeneration after various mechanical or chemical injuries was studied histologically in relation to the genesis of bladder cancer. In this study transurethral cauterization was performed on female Sprague-Dawley rats to cause a fulgurated ulcer on the bladder mucosa. By light microscopy, the acute changes at the fulguration sites showed bleeding ulcerated lesions followed by infiltration of inflammatory cells. Nodular or papillary regenerative hyperplasia of the urothelium was observed in later stages. By scanning electron microscopy, regenerative urothelial cells with short microvilli on the luminal surface were observed. The regenerative hyperplasia was most prominent on Days 7 and 14, after the cauterization, and disappeared by Day 28. In conclusion, a reversible, regenerative hyperplasia of the rat urothelium was induced by transurethral fulguration.
This regenerative change may be useful as a model of bladder carcinogenesis.