Progressive Vascular Damage May Lead to Bladder Underactivity in Rats

Purpose: We assessed whether progressive vascular damage causes bladder underactivity in rats. Materials and Methods: Adult male Sprague Dawley (R) rats were divided into 4 groups. Controls received a regular diet and tap water. The L-NAME group received a 2% cholesterol diet and L-NAME (3 mg/ml) dissolved in drinking water. The arterial injury group underwent balloon endothelial injury of the common iliac arteries and received a 2% cholesterol diet and tap water after injury. The arterial injury/L-NAME group also received L-NAME dissolved in drinking water. At 8 weeks urodynamics were performed, bladder tissue was harvested for pharmacological studies, and the iliac arteries and bladders were histologically examined. Results: Iliac arteries from the injury and injury/L-NAME groups showed neointimal formation and luminal occlusion but arteries from the L-NAME group did not. In theL-NAMEand injury groups bladder capacity and voided volume were less than in controls. Conversely, in the injury/L-NAME group these cystometric parameters were significantly greater than in the other groups. Post-void residual volume in the injury/L-NAME group tended to increase compared with the other groups. Contractile responses of bladder strips to various stimuli in the L-NAME, injury and injury/L-NAME groups were significantly less than in controls and the lowest in the injury/L-NAME group. The injury and injury/L-NAME groups showed a significantly increased percent of collagen compared to controls. Conclusions: Pelvic arterial occlusive disease plus vascular endothelial dysfunction may cause progressive vascular damage resulting in bladder dysfunction that develops from bladder hyperactivity to bladder underactivity.