Early metabolic, functional and histological changes in a rat ileal-augmented bladder model

An animal model of female Wistar species of rats was developed to study the early effects of ileocystoplasty.

Bladder augmentation using ileum and a sham operation (cistostomy) were performed in 14 and 6 female Wistar rats, rispectively. Urine was obtained for culture and urinalysis in all rats at the time of operation and at the time of the sacrifice. Seven rats underwent ileocystoplasty and three shams were sacrificed after one and three months. In all rats sacrificed three months after ileocystoplasty, blood sample drawn for serum electrolytes, blood urea, nitrogen creatine and bicarbonate was performed. Post mortem histopathological examination of the ileal patch and of kidneys was performed.

The cultures of the urine were positive in 1 out 7 (14.3%) and in 4 out 7 (57%) after one and three months after ileocystoplasty, respectively. Urinary pH of the augmented group was significantly higher in treated rats than in shams (p < 0.05). At sacrifice three months post operatively, the serum chloride concentration was significantly higher in augmented than shams (p < 0.05). Bladder calculi were formed in 28.6% of ileocystoplasty. Histopathological examination of the enteropatch showed urothelialization of the graft and kidneys showed a significant glomerular depletion.

Our data confirm an early significant enhancement of urinary pH in rats underwent ileocystoplasty and the stone formation is a frequent event. Already three months after ileocystoplasty urothelialization extended from the side of anastomosis towards the central portion of the ileal graft. Moreover, a significant improvement of serum creatine, sign of glomerular overload and progressive glomerular depletion were recorded in treated rats, probably as a consequence of water and electrolyte resoption through the intestinal graft.