Defunctionalized bladders: Effects before and after refunctionalization in an animal model

Purpose: Bladder behavior after refunctionalization is usually unpredictable. We comparatively analyze various aspects of bladder defunctionalization and subsequent refunctionalization using an animal model. Materials and Methods: A total of 18 rabbits were divided equally into 3 groups. Animals in group 1 underwent 2 successive surgical procedures, including bladder division and reattachment. Bladder division was performed by hemisecting the bladder from dome to trigone into a functioning and nonfunctioning chamber. Bladder reattachment was achieved by reanastomosing both hemibladders. Group 2 animals underwent sham operations, and group 3 animals were age matched normal controls. Serial urodynamic studies and fluoroscopic cystograms were performed in all animals. Gross, histochemical (hematoxylin and eosin, Masson's trichrome and Sirius red) and immunocytochemical (α-actin, collagen I and III) analyses, collagen content determination and organ bath studies were performed. Results: The defunctionalized hemibladders demonstrated lower wet weight, capacity and compliance compared to the functional contralateral and normal control bladders. Refunctionalization of the bladders resulted in a progressive recovery of capacity and compliance with time. The bladder contractile response and connective tissue-to-muscle ratio were abnormal in the defunctionalized segments but normalized after bladder refunctionalization. Conclusions: Defunctionalization results in remarkable alterations in bladder growth, capacity, compliance and distribution of connective tissue. However, these bladders demonstrate an innate capacity to recover from these alterations following refunctionalization.