Experimental urolithiasis in the bladder of rats.

Abstract

Vesical foreign bodies readily lead to urolith formation but not in Brattleboro rats with diabetes insipidus. This experiment was designed to examine the roles of vesical foreign bodies, urine osmolality, and vesical infection in the formation of uroliths and associated reactive urothelial hyperplasia. ADH-deficient Brattleboro rats received surgical insertion of a silk suture in the bladder. Their bladders were infected with intravesical injection of urease positive P. vulgaris, while controls were similarly injected with sterile Ringer's sol. They received daily injections of either pitressin tannate in oil (1 U/kg body weight) or peanut oil. Urine flow rate, urine osmolality, urine culture, and gross and light microscopic examinations of the bladders were carried out at the end of 4th week. The results indicated that uroliths readily formed in the presence of all three factors; vesical foreign bodies, high urine osmolality, and infection, but not as readily in the presence of two or less of these three factors. The urothelial hyperplasia was prominent in infected bladders followed by non-infected bladder with high osmolar and low osmolar urine in this order.