Effect of suburethral prolene mesh for suburethral function and histology in a stress urinary incontinence mouse model

Objectives: To create a mouse model pertaining to mesh-elicited suburethral functional and histological changes after vaginal distention, and to examine the possible mechanism behind these complications. Methods: We divided 48 virgin female C57BL/6 mice into four groups: vaginal distention alone, vaginal distention followed by prolene mesh implantation, vaginal distention followed by sham mesh implantation and untreated control. Each group was divided into two subgroups for conscious cystometrogram, leak-point pressure testing and harvesting of suburethral tissue 4 or 10 days after vaginal distention. The suburethral tissues underwent immunohistochemistry and western blot analysis of nerve growth factor, matrix metalloproteinase 2 and tissue inhibitor of metalloproteinase 2. Urodynamic results were compared among groups using one way ANOVA, with Tukey's multiple comparisons post-test for pair wise comparisons. Results: Leak-point pressure in the vaginal distention and vaginal distention + sham mesh groups were significantly lower than in the control and vaginal distention + mesh groups at day 4. Leak-point pressure in the vaginal distention + mesh group were significantly higher than in the other three groups at both day 4 and 10. Immunohistochemistry and western blotting showed increased matrix metalloproteinase 2 and tissue inhibitor of metalloproteinase 2 levels in the vaginal distention + mesh group at day 4 and 10. Furthermore, nerve growth factor expression was increased in the same area and same group at 10 days. Conclusions: Increased suburethral tissue matrix metalloproteinase and nerve growth factor expression might be related to tissue remodeling after prolene mesh implantation for stress urinary incontinence.