Korean J Urol.
2003 Oct;44(10):1058-1063.
What Causes Bladder Fibrosis?: Abnormal Innervation or Abnormal Bladder Dynamics
- Affiliations
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- 1Brain Korea 21 Project for Medical Science.
- 2Department of Urology, College of Medicine, Yonsei University, Korea. swhan@yumc.yonsei.ac.kr
- 3Department of Urology, Hallym University College of Medicine, Chuncheon, Korea.
Abstract
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PURPOSE: Bladder tissue fibrosis is characterized by the abnormal deposition of connective tissue within different layers of the bladder wall, resulting in "non-compliance". The different etiologies of bladder fibrosis are either neurogenic, which encompasses myelodysplasia and spinal cord injury, or nonneurogenic, due to a bladder outlet obstruction. In this study, bladder fibrosis was examined to see if it was due to the effect of an abnormal innervation or to abnormal bladder dynamics.
MATERIALS AND METHODS
Thirty-five male Sprague-Dawley rats (250-300g) were divided into four groups; the normal (n=5), bilateral pelvic nerve transection; denervation (n=10), vesicostomy (n=10) and vesicostomy after denervation (n=10) groups. After 4 weeks, the bladders of the animals in each group were obtained. In the histological study, the collagen to muscle ratio from Masson's trichrome staining, and the elastin density (%) from Van Gieson staining, were determined using a Metamorph ver 4.6r5 image analyzer. The TGF-beta1 and collagen III protein expressions were detected by Western blotting.
RESULTS
The collagen to muscle ratios of the normal, vesicostomy, denervation and vesicostomy after denervation groups were; 0.67+/-0.04*, 0.67+/-0.04*, 1.25+/-0.03* and 0.96+/-0.02 (*p<0.001) and the elastin densities were 14.73+/-1.09**, 16.38+/-2.27, 23.6+/-1.93** and 18.35+/-1.27, respectively (**p<0.01). From the Western blotting, the denervation group showed significantly increased TGF-beta1 and collagen III protein expressions compared with the normal and vesicostomy groups.
CONCLUSIONS
The orders of the collagen to muscle ratio and the deposition of elastin were; denervation>vesicostomy after denervation>vesicostomy>normal from the histological study. The levels of TGF-beta1 and of collagen III in the denervation group were higher than those in the vesicostomy after denervation group. The above findings show that pressure and nerve innervation in the bladder both have significant effects on the process of bladder fibrosis. Meanwhile, a vesicostomy could reduce the fibrotic effect caused by denervation, although this is not complete.
