Regional Differences in Rat Vaginal Smooth Muscle Contractility and Morphology

Skoczylas, Laura C.; Jallah, Zegbeh; Sugino, Yoshio; Stein, Suzan; Feola, Andrew; Yoshimura, Naoki; Moalli, Pamela

doi:10.1177/1933719112472733

Cited by 31 publications

(27 citation statements)

References 12 publications

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“…Our results in sheep are in line with a study in rats which showed significant regional differences of vaginal wall contractility [9]. We restricted our testing to the posterior vaginal wall tissue due to the different anatomical location of the urethral orifice between sheep and humans.…”

Section: Discussionsupporting

confidence: 88%

Regional Variation in Tissue Composition and Biomechanical Properties of Postmenopausal Ovine and Human Vagina

et al. 2014

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ObjectiveThere are increasing numbers of reports describing human vaginal tissue composition in women with and without pelvic organ prolapse with conflicting results. The aim of this study was to compare ovine and human posterior vaginal tissue in terms of histological and biochemical tissue composition and to assess passive biomechanical properties of ovine vagina to further characterise this animal model for pelvic organ prolapse research.Study DesignVaginal tissue was collected from ovariectomised sheep (n = 6) and from postmenopausal women (n = 7) from the proximal, middle and distal thirds. Tissue histology was analyzed using Masson's Trichrome staining; total collagen was quantified by hydroxyproline assays, collagen III/I+III ratios by delayed reduction SDS PAGE, glycosaminoglycans by dimethylmethylene blue assay, and elastic tissue associated proteins (ETAP) by amino acid analysis. Young's modulus, maximum stress/strain, and permanent strain following cyclic loading were determined in ovine vagina.ResultsBoth sheep and human vaginal tissue showed comparable tissue composition. Ovine vaginal tissue showed significantly higher total collagen and glycosaminoglycan values (p<0.05) nearest the cervix. No significant differences were found along the length of the human vagina for collagen, GAG or ETAP content. The proximal region was the stiffest (Young's modulus, p<0.05), strongest (maximum stress, p<0.05) compared to distal region, and most elastic (permanent strain).ConclusionSheep tissue composition and mechanical properties showed regional differences along the postmenopausal vaginal wall not apparent in human vagina, although the absolute content of proteins were similar. Knowledge of this baseline variation in the composition and mechanical properties of the vaginal wall will assist future studies using sheep as a model for vaginal surgery.

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Section: Discussionsupporting

confidence: 88%

Regional Variation in Tissue Composition and Biomechanical Properties of Postmenopausal Ovine and Human Vagina

et al. 2014

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“…This observation may contribute to the hypersensitivity described above. The M2 and M3 receptors have been previously demonstrated in vaginal tissue and muscarinic activation induces contraction, although their physiologic role remains unknown 14,23 . The upregulation of M2 we demonstrate at 3 days, might therefore further explain the earlier described hypersensitivity.…”

Section: Discussionsupporting

confidence: 57%

“…To document the functional effect of PNC + VD on the smooth muscle layer of the vaginal wall, strips of vaginal tissue were tested in organ baths, as described previously by Skoczylas et al 14 After euthanasia, the vagina excised in toto and placed in ice cold Krebs solution (in mM: 118 NaCl, 4.7 KCl, 3.3 MgSO 4 , 5.5 glucose, 2 Na pyruvate, 1.5 KH 2 PO 4 , 25 NaHCO 3 , 3.3 CaCl 2 ). A circumferential strip from the middle vagina measuring 3 × 7 mm was suspended with custom‐made tissue clamps, which were attached to a stationary hook on one side and the force transducer (Harvard Apparatus, Holliston, MA) on the other side.…”

Section: Methodsmentioning

confidence: 99%

“…Contractile responses were recorded with custom‐made software and traces were analyzed with OriginPro 6.1 software (Origin Lab Corp, Northampton, MA). Strips were calibrated for 60 minutes, pretensioning was done by applying a total of 2 g preload by applying 0.5 g every 15 minutes until a final resting tension between 0.1 and 0.2 g 14 . Contractile responses to increasing concentrations of KCl (10 to 120 mmol/L) were measured.…”

Section: Methodsmentioning

confidence: 99%

“…6‐µm slices were stained with Hematoxylin and Eosin (H&E), Masson's trichrome. Alpha smooth muscle actin (α‐SMA) staining was used to assess smooth muscle and CD‐34, a marker for endothelial cells, to assess vasculature 14 . Histological evaluation and images were done on an Axioplan 40 microscope (Zeiss, Oberkochen, Germany) using the ZEN 2 lite software.…”

Section: Methodsmentioning

confidence: 99%

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Simulated vaginal delivery causes transients vaginal smooth muscle hypersensitivity and urethral sphincter dysfunction

Callewaert

Cunha

Dewulf

et al. 2020

Neurourology and Urodynamics

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Background Although pelvic floor dysfunction (PFD) has a multifactorial etiology, pregnancy and childbirth are considered crucial events predisposing to urinary incontinence as well as pelvic organ prolapse, which are highly prevalent. Rats are the most frequently used animal model and pudendal nerve crush (PNC) and vaginal distension (VD) are often used to mimic vaginal delivery. Objective To document the time course of events after simulated vaginal delivery (SVD) on the urethral sphincter and the vaginal smooth muscle layer. Materials and Methods Virgin female Sprague‐Dawley rats were subjected to SVD (PNC + VD) or sham surgery and evaluated at 7, 14, 21, and 42 days after the injury. Urethral function was determined in vivo by microultrasound during cystometry and vaginal smooth muscle layer was harvested for in vitro pharmacologic investigation by isometric tension recording. Furthermore, vaginal and urethral samples were investigated by immunohistochemistry and real‐time quantitative polymerase chain reaction. Results Microultrasound showed no bursting of the urethral sphincter in the SVD group at 7 days with a functional recovery starting at 14 days, and normal bursting at 21 and 42 days. Vaginal smooth muscle showed higher sensitivity to carbachol at 14 and 21 days after injury; however, at 42 days, its sensitivity decreased when compared with sham. Conclusion SVD induces urethral dysfunction and a shift in vaginal smooth muscle contractile responses to carbachol.

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New Zealand white rabbit: a novel model for prolapse mesh implantation via a lumbar colpopexy

et al. 2019

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Introduction and hypothesis-New Zealand white rabbits are an inexpensive large-animal model. This study explored the rabbit as a model for mesh-augmented colpopexy using the intraabdominal vagina. We hypothesized that polypropylene mesh would negatively impact rabbit vaginal smooth muscle (VSM) morphology and contractile function, similar to the nonhuman primate (NHP)-the established model for prolapse mesh evaluation. Methods-Restorelle was implanted onto the vagina of ten rabbits via lumbar colpopexy after a hysterectomy. Ten rabbits served as sham. Twelve weeks post-implantation, the vagina was excised and VSM morphology and vaginal contractility were assessed. Outcome measures were compared using independent samples t and Mann-Whitney U tests with a Bonferroni correction, where appropriate. Results from the rabbits were compared with published NHP data. Results-Animals had similar age, parity and BMI. VSM was 18% thinner after Restorelle implantation, P = 0.027. Vaginal contractility was 43% decreased in response to 120 mM KCl (P = 0.003), similar to the 46% reduction observed in the NHP vagina implanted with Restorelle (P = 0.027). Three meshes wrinkled in vivo, resulting in dramatic thinning of the underlying vagina in the area of the mesh causing a mesh exposure. Conclusions-Polypropylene mesh negatively impacts VSM morphology and vaginal contractility in the rabbit, similar to the NHP, suggesting that the rabbit may serve as an alternative large-animal model. The vaginal thinning and appearance of a mesh exposure in the area of a mesh wrinkle suggest the rabbit may also serve as a model for understanding the pathophysiology of mesh exposure.

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Regional Differences in Rat Vaginal Smooth Muscle Contractility and Morphology

Cited by 31 publications

References 12 publications

Regional Variation in Tissue Composition and Biomechanical Properties of Postmenopausal Ovine and Human Vagina

Regional Variation in Tissue Composition and Biomechanical Properties of Postmenopausal Ovine and Human Vagina

Simulated vaginal delivery causes transients vaginal smooth muscle hypersensitivity and urethral sphincter dysfunction

New Zealand white rabbit: a novel model for prolapse mesh implantation via a lumbar colpopexy

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