Loss of integrity of the protective impermeability barrier in the urothelium has been identified as significant in bladder dysfunction. In this study we tested the theory that the luminal layer of glycosaminoglycans (GAG) serves as an important component of the barrier function. The peptide polycation protamine sulfate (PS), 1 mg/ml, was instilled intravesically for 10 minutes into rat bladders Chondroitinace ABC (ChABC), 63 IU/ml, was instilled into an additional 6 rats for 30 min to digest the GAG layer. Unmanipulated controls and sham-injected controls were also performed. After 24 hours, the rats were euthanized, the bladders were removed and permeability was assessed in the Ussing chamber and by diffusion of FITC-labeled dextran (4 KD) to measure macromolecular permeability. The status of tight junctions was assessed by immunofluorescence and electron microscopy. In control and sham treated rat bladders, the transepithelial electrical resistance (TEER) were means of 2.5 ± 1.1 kΩcm2 vs 2.6 ±1.1 kΩcm2 vs 1.2 ± 0.5 kΩcm2 and 1.01 ± 0.7 kΩcm2 in the PS-treated and ChABC-treated rat bladders (p=0.0016 and p=0.0039 respectively). Similar differences were seen in dextran permeability. Histopathology showed a mild inflammation following PS treatment, but the ChABC-treated bladders were indistinguishable from controls. Tight junctions generally remained intact. ChABC digestion alone induced bladder permeability, confirming the importance of the GAG layer to the bladder barrier function and supports that loss of the GAG layer seen in bladder biopsies of IC patients could be a significant factor producing symptoms for at least some IC/PBS patients.
- Urinary bladder
- interstitial cystitis
- animal models
- Copyright © 2015, American Journal of Physiology - Renal Physiology