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High‐frequency micro‐ultrasound: A novel method to assess external urethral sphincter function in rats following simulated birth injury
Author(s) -
Hakim Lukman,
Endo Masayuki,
Feola Andrew,
Soebadi Doddy M.,
Deprest Jan,
De Ridder Dirk,
Albersen Maarten,
Van der Aa Frank
Publication year - 2015
Publication title -
neurourology and urodynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 90
eISSN - 1520-6777
pISSN - 0733-2467
DOI - 10.1002/nau.22555
Subject(s) - medicine , ultrasound , urology , urethral sphincter , urinary incontinence , contraction (grammar) , urethra , distension , urinary system , surgery , radiology
Aims We evaluated external urethral sphincter (EUS) function using high‐frequency micro‐ultrasound (US) in rats that were either uninjured (Control, C) or underwent vaginal distension (VD) as a substitute for vaginal birth injury induced stress urinary incontinence (SUI). Methods Thirteen female nulliparous Sprague–Dawley rats of 12 weeks were divided into two groups, either C (n = 6) or VD (n = 7). Vaginal balloon distension was performed under pentobarbital anesthesia for 4 hours. Five days after the injury, all animals underwent US assessment of the urethra during high‐rate bladder filling and urine leakage/voiding. Urinary leakage, the presence, absence, and pattern of EUS bursting during the voiding phase were registered, and pre‐determined parameters of intercontraction interval (ICI), length of contraction (LOC), and rate of contraction (ROC) were registered. Results Our ultrasound findings consistently showed the presence of rhythmic EUS bursting in all of the C rats (6/6), which were absent in all VD rats (0/7). The mean of ROC, ICI, and LOC in C group were 3.02 ± 0.12 contractions/sec, 471.43 ± 17.9 msec, and 103.41 ± 3.28 msec, respectively. Conclusions Pre‐determined parameters of LOC, ICI, and ROC during US provide objective and measurable data on EUS function. US showed the total disappearance of EUS bursting in the VD group as compared to the C group. These results indicate that ultrasound testing may become a valuable non‐invasive tool in future translational studies to investigate SUI/urethral function in rat models. Neurourol. Urodynam. 34:264–269, 2015 . © 2014 Wiley Periodicals, Inc.