Author:
Abe-Takahashi Yui,Kitta Takeya,Ouchi Mifuka,Chiba Hiroki,Higuchi Madoka,Togo Mio,Kusakabe Naohisa,Kakizaki Hidehiro,Shinohara Nobuo
Abstract
Abstract
Objective
This study investigated morphological changes in the composition of the pelvic floor muscles, degree of atrophy, and urethral function in a rat of simulated birth trauma induced by vaginal distension (VD) model.
Methods
Female Sprague–Dawley rats were classified into four groups: a sham group, and 1, 2, and 4 weeks post-VD (1 W, 2 W, and 4 W, respectively) groups. We measured the amplitude of urethral response to electrical stimulation (A-URE) to evaluate urethral function. After measuring the muscle wet weight of the pubococcygeus (Pcm) and iliococcygeus (Icm) muscles, histochemical staining was used to classify muscle fibers into Types I, IIa, and IIb, and the occupancy and cross-sectional area of each muscle fiber were determined.
Results
There were 24 Sprague–Dawley rats used. A-URE was significantly lower in the 1 W group versus the other groups. Muscle wet weight was significantly lower in the VD groups versus the sham group for Pcm. The cross-sectional area of Type I Pcm and Icm was significantly lower in the VD groups versus the sham group. Type I muscle fiber composition in Pcm was significantly lower in the VD groups versus the sham groupand lowest in the 2 W group. Type I muscle fiber composition in Icm was significantly lower in the 2 and 4 W groups versus the sham group.
Conclusion
Muscle atrophy and changes in muscle composition in the pelvic floor muscles were observed even after improvements in urethral function. These results may provide insight into the pathogenesis of stress urinary incontinence after VD.
Publisher
Springer Science and Business Media LLC
Subject
Obstetrics and Gynecology
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