Impact of pregnancy and childbirth on female rats’ urethral nerve fibers

Rocha, Marco; Sartori, Marair Grácio Ferreira; Simões, Manuel de Jesus; Herrmann, Viviane; Baracat, Edmund Chada; Lima, Geraldo Rodrigues de; Girão, Manoel Joâo Batista Castello

doi:10.1007/s00192-007-0355-3

Cited by 11 publications

(12 citation statements)

References 49 publications

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“…However, although not statistically significant, Figure clearly showed that MYOD1 and MYOG gene expression were lower in the EST group compared with untreated rats. Electric current potentially improves muscle repair and the evaluation moments (7 and 30 days after trauma) failed to detect the exact moment of this mechanism . The results by Russo et al corroborate our findings.…”

Section: Discussionsupporting

confidence: 88%

The molecular effects of electrical stimulation on the muscle components of the urethra of female rats after trauma by vaginal distention

Salerno

Bortolini

Gomes

et al. 2019

Neurourology and Urodynamics

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Aims: To evaluate the expression of genes and proteins related to the urethral muscles of female rats after trauma by vaginal distention (VD) and after electrical stimulation therapy (EST). Methods:We compared the urethras of four groups of 20 animals each: control without trauma (C), 7 (recent-trauma) and 30 days (late-trauma) post-VD, and VDtreated with EST. We evaluated the expression of myogenic regulatory factors MYOD1 and myogenin (MYOG); skeletal muscle myosin heavy chain 1, 2, and 3 (MYH1, MYH2, and MYH3); smooth muscle MYH11; and myosin light chain 9 (MYL9). We used real-time quantitative polymerase chain reaction, Western blot analysis, and immunohistochemistry. Results: MYOD1 and MYOG genes were overexpressed in the recent-trauma group compared with the other groups (P < .05). MYH1 and MYH3 genes were upregulated in the recent-trauma group compared with the control and EST groups (P < .05). The MYH2 gene was overexpressed in the late-trauma group (P < .05), while the MYH2 protein was significantly increased in the EST group compared with control, recent-trauma and late-trauma groups by 5-, 3-, and 2.7-fold change, respectively (P < .05). MYL9 and MYH11 messenger RNA were overexpressed in both trauma groups compared with control and EST groups (P < .05). MYH11 protein was not different among the study groups (P > .05). Conclusions: EST enhances the recovery of the damaged urethral tissue of rats mainly by acting on the striated-muscle components. The MYH2 pathway underlies the positive effects of EST in the external urethral sphincter.

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Section: Discussionsupporting

confidence: 88%

The molecular effects of electrical stimulation on the muscle components of the urethra of female rats after trauma by vaginal distention

Salerno

Bortolini

Gomes

et al. 2019

Neurourology and Urodynamics

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“…Even though there are differences between multiparous and nulliparous rats, VD is not innocuous in multiparous animals. It increases the percent of rats with urine leakage and the damage to urethral striated muscle and nerve fibers (45,46), from which we conclude that the VD model in nulliparous animals is suitable to mimic prolonged vaginal parturition, with the consideration that in some variables, the magnitude of the VD-induced damage may differ between nulliparous vs delivery groups.…”

Section: 56)mentioning

confidence: 82%

Neuroanatomic and behavioral correlates of urinary dysfunction induced by vaginal distension in rats

Palacios-Galicia

Juárez

Morán

et al. 2016

American Journal of Physiology-Renal Physiology

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-The aim of the present study was to use a model of simulated human childbirth in rats to determine the damage to genitourinary structures and behavioral signs of urinary dysfunction induced by vaginal distension (VD) in female rats. In experiment 1, the length of the genitourinary tract and the nerves associated with it were measured immediately after simulated human delivery induced by VD or sham (SH) procedures. Electroneurograms of the dorsal nerve of the clitoris (DNC) were also recorded. In experiment 2, histological characteristics of the bladder and major pelvic ganglion of VD and SH rats were evaluated. In experiment 3, urinary parameters were determined in conscious animals during 6 h of dark and 6 h of light before and 3 days after VD or SH procedures. VD significantly increased distal vagina width (P Ͻ 0.001) and the length of the motor branch of the sacral plexus (P Ͻ 0.05), DNC (P Ͻ 0.05), and vesical nerves (P Ͻ 0.01) and decreased DNC frequency and amplitude of firing. VD occluded the pelvic urethra, inducing urinary retention, hematomas in the bladder, and thinness of the epithelial (P Ͻ 0.05) and detrusor (P Ͻ 0.01) layers of the bladder. Major pelvic ganglion parameters were not modified after VD. Rats dripped urine in unusual places to void, without the stereotyped behavior of micturition after VD. The neuroanatomic injuries after VD occur alongside behavioral signs of urinary incontinence as determined by a new behavioral tool for assessing micturition in conscious animals. external urethral sphincter; dorsal nerve of the clitoris; major pelvic ganglion; micturition MICTURITION consists of two phases: storage and urine expulsion. During storage, the detrusor is relaxed while the bladder neck and urethra are activated, preventing involuntary bladder emptying (11). Extrinsic elements such as the levator ani muscle also contribute to the maintenance of continence (3). When the bladder reaches its threshold volume, spinal and supraspinal reflexes are triggered to induce bladder contraction and urethral relaxation, and urine flows through the urethra (11). Damage to the lower urinary tract and/or its innervation can induce urinary dysfunction (3,29,41).Urinary dysfunction affects the health of many women (60). Stress urinary incontinence has been described as involuntary loss of urine during effort and is the most prevalent urinary disorder related to vaginal childbirth, which is known to injure the pudendal nerve and denervate the external urethral sphincter (EUS) (3, 15, 57).Maternal pelvic viscera and nerve damage results from the difficulty of human childbirth due the large fetal head and brain relative to the maternal pelvis size. Neonates at birth have heads that are close to the size of the maternal birth canal through which they must pass during the second stage of parturition (48). Births of fetuses over 4 kg or fetal malposition often prolong parturition (30), retaining the fetus in the pelvic cavity, the main anatomic resistance to fetal expulsion. Prolonged second stage of parturition...

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“…The anterior location of the fetal head afforded by a wider pelvis might directly damage the urethra or urethral supports, similar to the vaginal delivery-induced urethral changes seen in previously published animal models. (16, 17) Alternatively, trauma from the delivery may unmask preexisting poor urethral function that, prior to delivery of the newborn, was compensated for by urethral support and/or pelvic floor functioning. Interestingly, despite a two-fold higher rate of visible levator ani defects in the incontinent primiparas than the primiparous controls, we find no association between the rates of these muscle defects and the subpubic angle, suggesting that any birth trauma promoted by a wider subpubic angle is not reflected in the visible levator ani defects noted on MRI.…”

Section: Discussionmentioning

confidence: 99%

Bony pelvis dimensions in women with and without stress urinary incontinence

Berger

Doumouchtsis

DeLancey

2012

Neurourology and Urodynamics

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AIMS To test the null hypothesis that bony pelvis dimensions are similar in women with and without stress urinary incontinence, both in the postpartum and midlife periods. METHODS Secondary analyses were performed of two case-control studies comparing women with stress urinary incontinence to asymptomatic controls. One study examined primiparas in the first 9–12 months postpartum; the other study involved middle-aged women. Stress urinary incontinence was confirmed by full-bladder stress test. All subjects underwent pelvic magnetic resonance imaging. The interspinous and intertuberous diameters, subpubic angle and sacrococcygeal joint-to-the inferior pubic point distance were measured from the images independently by two authors. RESULTS In the young cohorts, we compared primiparas with de novo postpartum stress urinary incontinence to both continent primiparas and nulliparas. Postpartum stress urinary incontinence is associated with a wider subpubic angle. There is also a trend towards wider interspinous and intertuberous diameters in the stress-incontinent primiparas as compared to the continent cohorts, although this did not reach statistical significance with our sample sizes. By contrast, no significant differences in bony pelvis dimensions were identified when comparing middle-aged women with stress urinary incontinence and their continent controls. CONCLUSIONS Bony pelvis dimensions are different in women with stress urinary incontinence than in matched continent controls. However, these differences are only identified in young primiparas in the postpartum period, not in middle-aged women.

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Impact of pregnancy and childbirth on female rats’ urethral nerve fibers

Cited by 11 publications

References 49 publications

The molecular effects of electrical stimulation on the muscle components of the urethra of female rats after trauma by vaginal distention

The molecular effects of electrical stimulation on the muscle components of the urethra of female rats after trauma by vaginal distention

Neuroanatomic and behavioral correlates of urinary dysfunction induced by vaginal distension in rats

Bony pelvis dimensions in women with and without stress urinary incontinence

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