Initial Characterization of the Cellular Basis for Bladder Regeneration in a Rodent Model

Abstract

PurposeA better understanding of intrinsic mammalian organ regeneration would benefit the field regenerative medicine. Our prior work shows functional bladder recovery in rats after removal of ~70% of the bladder (subtotal cystectomy/STC). Our objective is to begin identifying the spatiotemporal characteristics of cellular response to STC.MethodsTrigone‐sparing STC was performed on 12‐week‐old female Fischer F344 rats. At 1, 3, 5, and 7 days post‐STC, bladders were harvested 2 hours after IP 50mg/kg 5‐Bromo‐2’‐deoxyuridine (BrdU). Fluorescent BrdU labeling was used to quantify and localize S‐phase cells within the bladder wall. Immunohistochemistry for Shh, Gli‐1 and BMP‐4 was also performed. Normal rat bladders served as controls.ResultsSparse BrdU labeling was observed in native bladders (Fig. 1). The total number of BrdU‐positive cells/400x HPF was significantly higher post‐STC at all time points. A time‐depended location change in the percentage of BrdU‐positive cells was seen. Increased positive staining for Shh, Gli‐1 and BMP‐4 was also noted post‐STC.ConclusionsSTC induced a robust proliferative response with quantifiable spatiotemporal characteristics and up‐regulation of key targets in the Shh developmental pathway. Future studies will identify the cell source(s) and details of the molecular pathways that modulate functional bladder regeneration.