Korean J Urol.  2008 Feb;49(2):160-167.

Changes in Corpus Cavernosum after Partial Bladder Outlet Obstruction in Rat

• Mo KI
• Lee HI
• Lee KS

Abstract

PURPOSE
Abnormalities of the relaxation and contraction of the corpus cavernosum can lead to erectile dysfunction. Therefore, we induced a partial bladder outlet obstruction(PBOO) in male rats, and investigated the mechanisms of penile dysfunction with endothelial nitric oxide synthase(eNOS), vascular endothelial growth factor(VEGF), endothelin-1(ET-1), and apoptosis of peri-vascular smooth muscle and connective tissue cells in the corpus cavernosum. MATERIALS AND METHODS: PBOO was induced in 13 Sprague-Dawley rats by placing a 25 gauge needle sheath around the urethra, then ligating the bladder neck with a 3-0 suture. Three week after surgery, distal penile tissues were dissected for immunohistochemical staining, immunoblotting, and TUNEL staining. RESULTS: The expression of eNOS and VEGF were significantly decreased, whereas the expression of ET-1 and apoptosis of perivascular smooth muscle and connective tissue cells were significantly increased in the corpus cavernosum. CONCLUSIONS: The significant increase of ET-1 and apoptosis along with decreased eNOS and VEGF could mediate erectile dysfunction.

Keyword

Partial bladder outlet obstruction; Endothelin-1; Endothelial nitric oxide synthase; Vascular endothelial growth factor; Apoptosis

MeSH Terms

Animals
Apoptosis
Connective Tissue Cells
Contracts
Endothelin-1
Erectile Dysfunction
Humans
Immunoblotting
In Situ Nick-End Labeling
Male
Muscle, Smooth
Neck
Needles
Nitric Oxide
Nitric Oxide Synthase Type III
Rats
Rats, Sprague-Dawley
Relaxation
Sutures
Urethra
Urinary Bladder
Urinary Bladder Neck Obstruction
Vascular Endothelial Growth Factor A
Endothelin-1
Nitric Oxide
Nitric Oxide Synthase Type III
Vascular Endothelial Growth Factor A

Figure

• 

  Fig. 1 Immunohistochemical identification of endothelin-1 (ET-1) in corpus cavernosum of the penis. ET-1 immunoreactivity is present in the endothelium of the small vessels in the corpus cavernosum. Rats with partial bladder outlet obstruction (PBOO) treatment showed increased ET-1 immunoreactivity (++++) (B) compared with sham-operated animals (A). Sham: sham-operated animals, BOO3W: PBOO treatment for 3 weeks. Scale bar: 50µm.

• 

  Fig. 2 Normalized expression of endothelial nitric oxide synthase (eNOS) in sham and partial bladder outlet obstruction (PBOO) rats. (A, Upper panel): Immunoblot reacted with an affinity purified anti-eNOS antibody reveals a 140 KDa band. β-tubulin was used as an internal control. (B, Lower panel): Densitometric analysis revealed that eNOS immunoreactivity is down-regulated by PBOO. *p<0.05.

• 

  Fig. 3 Normalized expression of vascular endothelial growth factor (VEGF) in sham and partial bladder outlet obstruction (PBOO) animals. (A, Upper panel): Immunoblot reacted with an affinity purified anti-VEGF antibody reveals a 49KDa band. β-tubulin was used as a internal control. (B, Lower panel): Densitometric analysis revealed that VEGF is down- regulated by PBOO. *p<0.05.

• 

  Fig. 4 Apoptotic cell death in the corpus cavernosum after partial bladder outlet obstruction (PBOO). Apoptosis was measured using the TUNEL method. Sham: no apoptotic cell death, PBOO: Brownish TUNEL positive cells (arrows) were significantly increased in the smooth muscle and connective tissue, Csm: smooth muscle cells, Cct: connective tissue, Cbv: small blood vessels. Scale bar: 50µm

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