Successful induction of stress urinary incontinence in mice by vaginal distension does not depend on the estrous cycle.

Abstract

OBJECTIVE: To determine if the performance of vaginal distension (VD) in different estrous cycle phases affects the successful induction of stress urinary incontinence in mice. METHODS: Female virgin C57BL/6 mice were distributed into 4 groups according to their estrous cycle phase: proestrus, estrus, metestrus, or diestrus. The estrous cycle was staged by examining vaginal smears, and the method was corroborated by histologic examination of the vagina in a subset of each group. Each group was divided into 4 subgroups for measurement of 24-hour micturition behavior and the leak point pressure (LPP) 4 or 20 days after VD or sham VD. RESULTS: Voiding events increased and mean void volume decreased 4 days, but not 20 days after VD, and the LPP was decreased 4 days, but not 20 days after VD compared with the corresponding sham group, regardless of the estrous cycle phase when VD was performed. There were no differences in 24-hour micturition behavior or LPP among the 4 different estrous cycle phases either in sham or VD group. CONCLUSION: Successful induction of reversible stress urinary incontinence in mice is not dependent on the estrous cycle.