Journal List > Korean J Urol > v.49(2) > 1005056

Mo, Lee, and Lee: Changes in Corpus Cavernosum after Partial Bladder Outlet Obstruction in Rat

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.

Figures and Tables

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.
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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.
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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.
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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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