TY - JOUR
T1 - The effect of ovariectomy and long-term estrogen replacement on bladder structure and function in the rat
AU - Fleischmann, Nicole
AU - Christ, George
AU - Sclafani, Theresa
AU - Melman, Arnold
PY - 2002/9
Y1 - 2002/9
N2 - 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.
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.
KW - Bladder
KW - Estrogen replacement therapy
KW - Menopause
KW - Rats, Sprague-Dawley
KW - Urinary incontinence
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U2 - 10.1016/S0022-5347(05)64637-X
DO - 10.1016/S0022-5347(05)64637-X
M3 - Article
C2 - 12187279
AN - SCOPUS:0036720264
SN - 0022-5347
VL - 168
SP - 1265
EP - 1268
JO - Journal of Urology
JF - Journal of Urology
IS - 3
ER -