Development of Bladder Carcinoma Following Portacaval Shunt in Rats

Abstract

Portacaval anastomosis (PCA) was first introduced by Eck (1877) and was investigated in a number of different animals. Lee et al. (1961; 1974) published a reliable method with low mortality in rats. The occurrence of urolithiasis in rats following portacaval anastomosis happened to be noticed by chance. It was published by Herz et al. (1972a, 1972b, 1973), who defined the portacaval shunt rat as an experimental model. Heine et al. (1979) described dysplastic and neoplastic changes of the bladder mucosa following portacaval anastomosis. His findings were confirmed by Duy et al. (1981); Grun et al. (1982), and Dubuisson et al. (1984). However, Wallace et al. (1984) found papillary hyperplasia, not neoplastic changes, always in the presence of urolithiasis. The results obtained so far regarding the development of bladder carcinoma following PC A differ, and our investigation intends to address the following questions: 1. Does a portocaval shunt in rats lead to neoplastic changes of the urinary bladder? 2. What is the sex distribution? 3. Do bladder neoplasms develop independently from urolithiasis, or can they be seen only in rats with bladder stones? 4. If the malignant changes are not caused by urolithiasis but are the result of excretion of a carcinogen as proposed by some — can then carcinogen concentration and tumor induction in the upper urinary tract be increased by unilateral nephrectomy?