Effect of extended-term estrogen on voiding in a postpartum ovariectomized rat model

Authors

  • Narihiko Hayashi Knuppe Molecular Urology Lab, Department of Urology, University of California, San Francisco, Calif.
  • Anthony J. Bella Knuppe Molecular Urology Lab, Department of Urology, University of California, San Francisco, Calif.
  • Guifang Wang Knuppe Molecular Urology Lab, Department of Urology, University of California, San Francisco, Calif.
  • Guiting Lin Knuppe Molecular Urology Lab, Department of Urology, University of California, San Francisco, Calif.
  • Donna Y. Deng Knuppe Molecular Urology Lab, Department of Urology, University of California, San Francisco, Calif.
  • Lora Nunes Knuppe Molecular Urology Lab, Department of Urology, University of California, San Francisco, Calif.
  • Tom F. Lue Knuppe Molecular Urology Lab, Department of Urology, University of California, San Francisco, Calif.

DOI:

https://doi.org/10.5489/cuaj.79

Abstract

Introduction: We tested the hypothesis that extended-term (5-week) estrogentherapy would negatively impact voiding function in a postpartum, ovariectomizedrat model.

Methods: Immediately after delivery, 30 primiparous Sprague–Dawley rats underwentintravaginal balloon dilation, followed by ovariectomy 1 week later. Cystometry at postpartum week 2 determined normal or abnormal voiding patterns.After randomization, one-half the normal and abnormal voiding ratsreceived 5 weeks of estrogen therapy, while the remainder received placebo. Estrogen effect was determined by repeat cystometry and immunohistochemical analysis of the urethra and vagina.

Results: Abnormal voiding increased from 60.0% to 73.3% in the estrogen treated group and declined from 60% to 33% for the placebo group. Rats were then divided into 4 groups for comparison: normal voiding versus placebo(group 1), abnormal voiding versus placebo (group 2), normal voiding versus estrogen (group 3) and abnormal voiding versus estrogen (group 4). Bladdercapacity, leak point pressure and maximum voiding pressure were mostdepressed in group 4. Estrogen treatment was associated with a significant downregulationof α1A and α1D-adrenoceptors in the urethral submucosa but an upregulationof nNOS in the urethral smooth muscle.

Conclusion: Extended-term estrogen therapy in a rat model of simulated birth trauma and ovariectomy resulted in a higher rate of incontinence. Immunohistochemical examination demonstrated significant downregulationof urethral α1A- and α1D-adrenoceptors and upregulation of neuronal nitric oxidesynthase (nNOS) in the urethra of estrogen-treated groups. These studies question the use of hormone replacement therapy in the treatment of postmenopausalincontinence.

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Published

2012-12-11

How to Cite

Hayashi, N., Bella, A. J., Wang, G., Lin, G., Deng, D. Y., Nunes, L., & Lue, T. F. (2012). Effect of extended-term estrogen on voiding in a postpartum ovariectomized rat model. Canadian Urological Association Journal, 1(3). https://doi.org/10.5489/cuaj.79

Issue

Vol. 1 No. 3 (2007): CUAJ September

Section

Original Research

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