The effect of ovariectomy and long-term estrogen replacement on bladder structure and function in the rat

Nicole Fleischmann, George Christ, Theresa Sclafani, Arnold Melman

Research output: Contribution to journalArticle

72 Citations (Scopus)

Abstract

Purpose: The use of estrogen replacement therapy for treating postmenopausal urinary incontinence is a controversial topic. We examined the behavioral, cystometric and histological changes that occur with long-term estrogen depletion and supplementation in rat bladders to determine the role of menopause in lower urinary tract dysfunction. Materials and Methods: A total of 40 female Sprague-Dawley rats were placed into 1 of 3 groups, including bilateral ovariectomy, bilateral ovariectomy plus estrogen replacement and control. The estrogen replaced group received a 0.25 mg. 16-week sustained release pellet (Innovative Research of America, Sanasota, Florida) placed subcutaneously. After surgery voiding frequency and volume were measured in 24-hour periods by placing animals in metabolic cages. After 16 weeks the rats underwent catheterization and continuous cystometry. The bladder was then removed and stained with Gomori trichrome. The collagen-to-smooth muscle density ratio was calculated for each specimen using current imaging software. Results: There was no significant difference in voiding patterns in the 3 groups, as measured by volume and voiding frequency. Cystometric data showed a trend toward higher voiding pressure, threshold pressure, baseline pressure and mean inter-voiding pressure in the ovariectomy group compared with the estrogen and control groups, although there was no statistical significance. Histological studies showed a higher mean collagen-to-smooth muscle ratio plus or minus standard deviation in the ovariectomy group (0.807 ± 0.204) than in the ovariectomy plus estrogen replacement (0.709 ± 0.118) and control (0.700 ± 0.129) groups (p <0.05). Furthermore, when histological and cystometric data were compared for individual samples, we found a direct correlation of mean inter-voiding pressure (a measure of bladder instability) with the collagen-to-smooth muscle ratio (p <0.05). Conclusions: Long-term estrogen replacement is beneficial for treating postmenopausal urinary incontinence.

Original languageEnglish (US)
Pages (from-to)1265-1268
Number of pages4
JournalJournal of Urology
Volume168
Issue number3
StatePublished - Sep 2002

Fingerprint

Estrogen Replacement Therapy
Ovariectomy
Urinary Bladder
Pressure
Smooth Muscle
Estrogens
Collagen
Urinary Incontinence
Menopause
Urinary Tract
Catheterization
Sprague Dawley Rats
Software
Control Groups
Research

Keywords

  • Bladder
  • Estrogen replacement therapy
  • Menopause
  • Rats, Sprague-Dawley
  • Urinary incontinence

ASJC Scopus subject areas

  • Urology

Cite this

Fleischmann, N., Christ, G., Sclafani, T., & Melman, A. (2002). The effect of ovariectomy and long-term estrogen replacement on bladder structure and function in the rat. Journal of Urology, 168(3), 1265-1268.

The effect of ovariectomy and long-term estrogen replacement on bladder structure and function in the rat. / Fleischmann, Nicole; Christ, George; Sclafani, Theresa; Melman, Arnold.

In: Journal of Urology, Vol. 168, No. 3, 09.2002, p. 1265-1268.

Research output: Contribution to journalArticle

Fleischmann, N, Christ, G, Sclafani, T & Melman, A 2002, 'The effect of ovariectomy and long-term estrogen replacement on bladder structure and function in the rat', Journal of Urology, vol. 168, no. 3, pp. 1265-1268.
Fleischmann, Nicole ; Christ, George ; Sclafani, Theresa ; Melman, Arnold. / The effect of ovariectomy and long-term estrogen replacement on bladder structure and function in the rat. In: Journal of Urology. 2002 ; Vol. 168, No. 3. pp. 1265-1268.
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AB - Purpose: The use of estrogen replacement therapy for treating postmenopausal urinary incontinence is a controversial topic. We examined the behavioral, cystometric and histological changes that occur with long-term estrogen depletion and supplementation in rat bladders to determine the role of menopause in lower urinary tract dysfunction. Materials and Methods: A total of 40 female Sprague-Dawley rats were placed into 1 of 3 groups, including bilateral ovariectomy, bilateral ovariectomy plus estrogen replacement and control. The estrogen replaced group received a 0.25 mg. 16-week sustained release pellet (Innovative Research of America, Sanasota, Florida) placed subcutaneously. After surgery voiding frequency and volume were measured in 24-hour periods by placing animals in metabolic cages. After 16 weeks the rats underwent catheterization and continuous cystometry. The bladder was then removed and stained with Gomori trichrome. The collagen-to-smooth muscle density ratio was calculated for each specimen using current imaging software. Results: There was no significant difference in voiding patterns in the 3 groups, as measured by volume and voiding frequency. Cystometric data showed a trend toward higher voiding pressure, threshold pressure, baseline pressure and mean inter-voiding pressure in the ovariectomy group compared with the estrogen and control groups, although there was no statistical significance. Histological studies showed a higher mean collagen-to-smooth muscle ratio plus or minus standard deviation in the ovariectomy group (0.807 ± 0.204) than in the ovariectomy plus estrogen replacement (0.709 ± 0.118) and control (0.700 ± 0.129) groups (p <0.05). Furthermore, when histological and cystometric data were compared for individual samples, we found a direct correlation of mean inter-voiding pressure (a measure of bladder instability) with the collagen-to-smooth muscle ratio (p <0.05). Conclusions: Long-term estrogen replacement is beneficial for treating postmenopausal urinary incontinence.

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