Dataset Information

Hormones restore biomechanical properties of the vagina and supportive tissues after surgical menopause in young rats.

ABSTRACT:

Objective

The objective of the study was to determine the impact of hormones on the biomechanical properties of the vagina and its supportive tissues following surgical menopause in young vs middle-aged rats.

Study design

Long-Evans rats (4-month virgin [n = 34], 4-month parous [n = 36], and 9-month parous [n = 34]), underwent ovariectomy (OVX) or sham surgery. OVX animals received hormones (estrogen [E2] or estrogen plus progesterone [E2 plus P4]), placebo, or a matrix metalloproteinase inhibitor (chemically modified tetracycline-8 [CMT-8]). Animals were euthanized after 8 weeks and the biomechanical properties of the vagina and supportive tissues determined. Data were analyzed using a 1-way analysis of variance and posthoc tests.

Results

OVX induced a rapid decline in the biomechanical properties of pelvic tissues in young but not middle-aged rats. Supplementation with E2, E2 plus P4, or CMT-8 restored tissues of young rats to control levels with no effect on middle-aged tissues. Parity did not have an impact on tissue behavior.

Conclusion

OVX has a differential effect on the tissues of young vs middle-aged rats.

SUBMITTER: Moalli PA

PROVIDER: S-EPMC2917050 | biostudies-literature | 2008 Aug

REPOSITORIES: biostudies-literature

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Publications

Hormones restore biomechanical properties of the vagina and supportive tissues after surgical menopause in young rats.

Moalli Pamela A PA Debes Kristen M KM Meyn Leslie A LA Howden Nancy S NS Abramowitch Steven D SD

American journal of obstetrics and gynecology 20080408 2

<h4>Objective</h4>The objective of the study was to determine the impact of hormones on the biomechanical properties of the vagina and its supportive tissues following surgical menopause in young vs middle-aged rats.<h4>Study design</h4>Long-Evans rats (4-month virgin [n = 34], 4-month parous [n = 36], and 9-month parous [n = 34]), underwent ovariectomy (OVX) or sham surgery. OVX animals received hormones (estrogen [E2] or estrogen plus progesterone [E2 plus P4]), placebo, or a matrix metallopro ...[more]

PMID: 18395691

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Project description:BackgroundSurgery is a common treatment for pelvic organ prolapse (POP); however, risk of recurrence and reoperation is high, resulting in a negative impact on quality of life and sexual function.AimTo examine the long-term effects of POP surgery and endogenous circulating ovarian hormones on the vagina and bladder.MethodsOur animal model simulated surgical injury of the vagina and bladder during POP surgery. Female Rowett nude rats were divided into 4 groups: intact control (IC), vaginal surgery only (V), ovariectomy only (O), and ovariectomy + vaginal surgery (OV). Rats were euthanized 10 weeks postsurgery. Proximal vagina and bladder dome/trigone underwent (1) organ bath myography to assess smooth muscle contractility; (2) real-time quantitative polymerase chain reaction to quantify mRNA expression of elastin, collagen I and III, and PGP9.5 (protein gene product 9.5); (3) enzyme-linked immunosorbent assay for protein quantification of elastin and collagen I and III; and (4) hematoxylin-eosin/immunohistochemistry staining.OutcomesThe primary outcome was tissue contractility as measured by organ bath myography. Secondary outcomes included gene and protein expression of collagen I and III and elastin.ResultsO and OV showed reduced vaginal wall contractility vs IC and V (P < .002). Bladder dome and trigone displayed different contractile patterns, with significant differences between O and OV (P < .05), suggesting a negative effect from surgery rather than ovariectomy. OV demonstrated consistent reductions in contractility and elastin/collagen protein expression for the vagina and bladder vs IC. V had similar contractility and increased collagen I expression vs IC, suggesting a protective effect of ovarian hormones. Vaginal epithelium thinning was confirmed in the ovariectomized groups (P = .001), although there was no statistical significance in muscularis thinning with surgery or ovariectomy. O, V, and OV showed significant downregulation of PGP9.5 mRNA expression vs IC.Clinical translationThese data allow researchers to gain insights into the long-term effects of surgery and deprivation of ovarian hormones. Future studies can use this animal model to investigate other mechanisms that may affect long-term tissue changes due to surgical intervention.Strengths and limitationsMajor strengths are long-term data on the effects of POP surgery and development of an animal model for future studies. However, the animal model limits our ability to extrapolate to humans, where tissue healing is modulated by many factors.ConclusionOur animal model provides evidence that ovarian hormone deprivation and POP surgery result in negative long-term effects on tissue function and extracellular matrix.

Project description:ImportanceRecent guidelines endorse using history of menopause before age 40 years to refine atherosclerotic cardiovascular disease risk assessments among middle-aged women. Robust data on cardiovascular disease risk in this population are lacking.ObjectiveTo examine the development of cardiovascular diseases and cardiovascular risk factors in women with natural and surgical menopause before age 40 years.Design, setting, and participantsCohort study (UK Biobank), with adult residents of the United Kingdom recruited between 2006 and 2010. Of women who were 40 to 69 years old and postmenopausal at study enrollment, 144 260 were eligible for inclusion. Follow-up occurred through August 2016.ExposuresNatural premature menopause (menopause before age 40 without oophorectomy) and surgical premature menopause (bilateral oophorectomy before age 40). Postmenopausal women without premature menopause served as the reference group.Main outcomes and measuresThe primary outcome was a composite of incident coronary artery disease, heart failure, aortic stenosis, mitral regurgitation, atrial fibrillation, ischemic stroke, peripheral artery disease, and venous thromboembolism. Secondary outcomes included individual components of the primary outcome, incident hypertension, hyperlipidemia, and type 2 diabetes.ResultsOf 144 260 postmenopausal women included (mean [SD] age at enrollment, 59.9 [5.4] years), 4904 (3.4%) had natural premature menopause and 644 (0.4%) had surgical premature menopause. Participants were followed up for a median of 7 years (interquartile range, 6.3-7.7). The primary outcome occurred in 5415 women (3.9%) with no premature menopause (incidence, 5.70/1000 woman-years), 292 women (6.0%) with natural premature menopause (incidence, 8.78/1000 woman-years) (difference vs no premature menopause, +3.08/1000 woman-years [95% CI, 2.06-4.10]; P < .001), and 49 women (7.6%) with surgical premature menopause (incidence, 11.27/1000 woman-years) (difference vs no premature menopause, +5.57/1000 woman-years [95% CI, 2.41-8.73]; P < .001). For the primary outcome, natural and surgical premature menopause were associated with hazard ratios of 1.36 (95% CI, 1.19-1.56; P < .001) and 1.87 (95% CI, 1.36-2.58; P < .001), respectively, after adjustment for conventional cardiovascular disease risk factors and use of menopausal hormone therapy.Conclusions and relevanceNatural and surgical premature menopause (before age 40 years) were associated with a small but statistically significant increased risk for a composite of cardiovascular diseases among postmenopausal women. Further research is needed to understand the mechanisms underlying these associations.

Dataset Information

Hormones restore biomechanical properties of the vagina and supportive tissues after surgical menopause in young rats.

Objective

Study design

Results

Conclusion

Publications

Hormones restore biomechanical properties of the vagina and supportive tissues after surgical menopause in young rats.

Similar Datasets

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