Evaluation of different techniques to create chronic urinary incontinence in the rat.

OBJECTIVE: To evaluate models for chronic urinary incontinence (UI) in the rat.

MATERIALS AND METHODS: Two models were fully evaluated: one of repeated dilatation of the vagina, simulating birth trauma, the vaginal dilatation (VD) group; the other, with surgical transposition of the urethra to a vertical position, the urethral transposition (UT) group. The VD rats were evaluated by the sneeze test. When negative, vaginal dilatation was repeated in a similar way. The UT group was evaluated by observation of continuous urine leakage. The leak-point pressure (LPP) was measured at study end in all the rats.

RESULTS: All the VD rats had occasional negative sneeze tests and all had to be dilated again. This resulted in persistent UI on sneeze testing for the entire period. In the UT group, 12 rats leaked continuously during the whole study period; in the other four UI became less at 4, 5, 6, and 7 weeks, respectively. The LPP in the rats with UI was significantly lower than in the respective control groups.

CONCLUSIONS: These models permit study of chronic stress UI and continuous UI in the rat. Spontaneous recovery of continence was seen mostly in the VD group.