CODE: 10.1 - Distribution, neurochemical characterization and plasticity of somatostatin-immunoreactive (SOM-IR) nerve fibers in the porcine urinary bladder induced by interstitial cystitis
Article published in Urologia Polska 2006/59/Suplement 1.

authors

Agnieszka Bossowska ¹, Joanna Wojtkiewicz ¹, Andrzej Borkowski ², Cezary Skobowiat ¹, Mariusz Majewski ¹, Piotr Radziszewski ¹

¹ Katedra Fizjologii Klinicznej Uniwersytetu Warmińsko-Mazurskiego w Olsztynie
² Katedra i Klinika Urologii AM w Warszawie

summary

Introduction. While the distribution and chemical coding of nerve fibers projecting to the urinary bladder of different animal species is relatively well documented, data concerning the distribution and neurochemical characterization of SOM-IR nerve fibers supplying the porcine urinary bladder are still incomplete. Moreover, there are no data on the possible changes in the distribution pattern and adaptive alternations of these nerve fibers after chemically-induced interstitial cystitis (IC) as yet.

Objectives. To study the IC-induced changes in the innervation pattern of porcine urinary bladder as a model of the human organ.

Materials and methods. The study was done on twelve sexually immature female pigs. The animals were divided on two experimental groups: CG - control animals and IC - animals with chemical induced interstitial cystitis. Serial whole-wall-thickness sections were obtained from the ventral bladder wall and from the trigone. The chemical coding of nerve fibers was studied by means of the routine double immunolabeling technique using the primary antisera (raised in different species) against SOM, substance P - SP, calcitonin gene-related peptide - CGRP, galanin - GAL and pituitary adenylate cyclase-activating peptide - PACAP. The antigen/antibody complex was visualized using secondary antisera against FITC and CY3, respectively.

Results. In the pig, SOM-IR nerve fibers formed very dense meshwork of fibers in the muscle layer of both the wall and the trigone of the organ, while only single SOM-containing nerves were observed in the submucosa and under the urothelium. SP, CGRP and PACAP were present in single nerve terminals lining in detrusor muscle and submucosa, while SP and/or CGRP-IR nerve fibers were observed sporadically under the urothelium. Moderate number of GAL-containing nerve terminals was observed in the muscle layer, whilst single GAL-IR nerve fibers were found in submucosa and under the urothelium. A proportion of neurons observed in the intramural ganglia of the urinary bladder contained simultaneously SOM and PACAP or SOM and GAL. In the IC animals, a significant decrease in the number of SOM- and GAL-IR nerve terminals was observed in detrusor muscle and under the urothelium. The number of nerve fibers containing SP, CGRP and SOM increased slightly in the submucosal layer.

Conclusions. The present study demonstrate that a distinct remodeling in the pattern of intramural nerve terminals occur in the course of a chemically induced IC in the wall and trigone of the porcine bladder. This may be indicative for a similar changes that may be, probably, attributable for the etiopathogenesis of this pathological process in the humans.