RU 06. Acomparison of three methods for establishing a rat model of female stress urinary incontinence

Objective: To establish the animal model of stress urinary incontinence (SUI) simulating birth injury and reduced levels of estrogen combined with pudendal neurectomy, so as to provide reliable and accessible experimental subjects for the study on SUI through identification and comparison of the model established.

Methods: A total of 40 healthy female Wistar rats were equally randomized into 4 groups: group I, control group; group II, colpectasia + ovariotomy group; group Ⅲ, pudendal neurectomy group; group Ⅳ, colpectasia + ovariotomy + pudendal neurectomy group. At postoperative 1, 4 and 8 W, urodynamic testing was performed on the four groups of rats and at 1 W, sneeze load test, to confirm the presence of SUI. Full-thickness urethra and pelvic floor muscles of rats were removed after 8 W for histological identification.

Results: Sneeze load test: There were respectively 6, 9 and 10 rats positive for the test in group II, III and IV, while no rats positive in group I. Leak point pressure (LPP): LPP was significantly lower in group III and IV than in group I and II (P<0.01); lower in group II than in group I (P<0.05); insignificantly different between group III and group IV (P>0.05). Histological manifestations: Compared with group Iand II, group III and IV had thinner full-thickness urethra, unobvious structure, muscle atrophy and lower urethral adventitial nerve distribution (S-100). Alpha-Actin (α-Actin) content in pelvic floor muscle tissue: significantly lower in group Ⅳ than in group I, II and III (P<0.01); lower in group III than in group I and II (P<0.05); insignificantly different between group I and II (P>0.05).

Conclusions: Combined with colpectasia and bilateral ovariotomy, bilateral pudendal neurectomy can establish the animal model of SUI successfully with a high success rate of modeling and good stability, which can realize more comprehensive simulation of SUI development under multiple factors and have characteristics closer to the occurrence of human SUI.