Korean J Urol.  2008 Jun;49(6):533-539.

The Effect of Estrogen on Expression of Neuronal and Endothelial Nitric Oxide Synthase and on Histologic Composition in Rat Bladder and Urethra

• Park SW
• Lee JZ

Abstract

PURPOSE: We investigated the effects of estrogen on the expression of neuronal nitric oxide synthase(nNOS) and on endothelial nitric oxide synthase(eNOS), and furthermore elucidated its effect on the histologic composition of the rat bladder and urethra.
MATERIALS AND METHODS
Forty-five mature female Sprague-Dawley rats (10-11 weeks, 235-250g) were randomly assigned to one of three groups: control group(C), oophorectomy group(O), or hormone(estradiol) replacement group(H). The degree of expression of nNOS and eNOS in bladder and urethral tissues was investigated using immunohistochemical staining, and tissue was described as mucosa, smooth muscle, or vessel. We also investigated changes in histologic composition using Masson's trichrome stain.
RESULTS
In bladder and urethra, the expression rates of nNOS and eNOS significantly increased in the O group, but decreased in the H group (p< 0.05), except for nNOS in the mucosa and smooth muscle of the bladder. The relative collagen ratios significantly increased in bladder and urethra in the O group, to 121.2+/-12.7% and 135.5+/-25.2%, respectively, but decreased to 95.6+/-15.2% and 93.7+/-12.8% in the H group, respectively (p<0.05).
CONCLUSIONS
These data suggest that estrogen replacement therapy decreases nNOS and eNOS expression and the collagen component in the urethra.

Keyword

Nitric oxide synthase; Collagen; Incontinence

MeSH Terms

Animals
Collagen
Estrogen Replacement Therapy
Estrogens
Female
Glycosaminoglycans
Humans
Mucous Membrane
Muscle, Smooth
Neurons
Nitric Oxide
Nitric Oxide Synthase
Nitric Oxide Synthase Type III
Ovariectomy
Rats
Rats, Sprague-Dawley
Urethra
Urinary Bladder
Collagen
Estrogens
Glycosaminoglycans
Nitric Oxide
Nitric Oxide Synthase
Nitric Oxide Synthase Type III

Figure

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  Fig. 1. The mean expression percentage of neuronal nitric oxide synthase (nNOS). A: bladder, B: urethra. Control: control group, Ox: oophorectomy group, HRT: hormone replacement group, ∗: p＜0.05 vs control group, †: p＜0.05 vs oophorectomy group.

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  Fig. 2. Immunoreactivity pattern for neuronal nitric oxide synthase (nNOS) in rat bladder and urethra. (A) control group, (B) oophorectomy group, (C) hormone replacement group (x200).

• 

  Fig. 3. Mean expression percentage of endothelial nitric oxide synthase (eNOS). A: bladder, B: urethra, Control: control group, Ox: oophorectomy group, HRT: hormone replacement group, ∗: p＜0.05 vs control group, †: p＜0.05 vs oophorectomy group.

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  Fig. 4. Immunoreactivity pattern for endothelial nitric oxide synthase (eNOS) in rat bladder and urethra. (A) control group, (B) oophorectomy group, (C) hormone replacement group (x200).

• 

  Fig. 5. Masson's trichrome staining of rat bladder and urethra (x200). (A) control group, (B) oophorectomy group, (C) hormone replacement group (x200).

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