Permeability of Pig Urinary Bladder Wall: Time and Concentration Dependent Effect of Chitosan

Abstract

Chitosan in 0.5% w/v concentration enhanced the permeability of the isolated pig urinary bladder wall by desquamation of the urothelium as ascertained in our previous study. The aim of the present work was to determine the time and concentration dependence of chitosan's effect on the permeation of a model drug into the bladder wall and to establish if the mechanism of permeation enhancement depends on the concentration of chitosan used. In the permeability studies performed by the use of diffusion cells, transport of a model drug moxifloxacin into the isolated pig urinary bladder wall was determined. For morphological observations of the urothelium in response to chitosan treatment scanning and transmission electron microscopy were applied. Within 90 min the effect of chitosan on the tissue amounts of moxifloxacin gradually increased and approached its plateau. In one hour even 0.0005% w/v dispersion of chitosan significantly enhanced the permeability of the pig urinary bladder wall for the model drug and at 0.001% w/v concentration the maximal effect on the tissue permeability was achieved. All concentrations of chitosan that significantly enhanced the permeability of the bladder wall triggered necrosis of superficial cells or desquamation of the urothelium. However, at lower concentrations and shorter exposure times the damage of the urothelium was limited to the changes in tight junctions. Chitosan was ascertained to increase the permeation of moxifloxacin into the urinary bladder wall in a time and concentration dependent manner.

Rapid differentiation of superficial urothelial cells after chitosan-induced desquamation

“…No deteriorating changes were found in te cells below the superficial layer, indicating that the small amounts of chitosan that very likely remain in the bladder after exchange of this polymer with PBS do not harm the cells. These findings are in agreement with our previous studies presenting a strict concentration dependent response of urothelial cells to chitosan dispersion (Kos et al 2006). The vitality of the new superficial cells was also confirmed by the instant formation of tight junctions and quick maturation of the apical membrane within the first 10 min after exposure of the cells to the luminal side of the bladder.…”

“…In a previous study, we found that the biopolymer chitosan, which is widely used as a food additive because of its ability to bind lipids and prevent their absorption into the digestive system, can cause destruction of the urothelium in ex vitro experiments on pieces of pig bladder (Kos et al 2006). The declared non-toxicity of chitosan made this biopolymer a promising inducer of desquamation of urothelial cells in vivo.…”

“…Ex vivo experiments on pig bladder urothelium confirmed that the application of chitosan caused dysfunction of tight junctions, but only at lower concentrations and for a shorter treatment time that did not result in significantly increased permeation of the model drug into the bladder wall. At higher concentrations of chitosan, necrosis and desquamation of urothelial cells was detected (Kos et al 2006). In vitro studies on bladder tumour cells proved that prolonged application of chitosan induced apoptosis by stimulating caspase-3 activation (Hasegawa et al 2001).…”

In vivo Evaluation of Mucoadhesive Nanoparticulate Docetaxel for Intravesical Treatment of Non–Muscle-Invasive Bladder Cancer

“…Our preliminary studies on the effects of HPGs on the urothelium have showed that HPG-C 8/10 -MePEG-NH 2 nanoparticles increase the permeability of the urinary bladder wall by causing changes to the urothelial barrier function and morphology through opening of tight junctions and exfoliation of the urothelium. These effects are similar to the effects on bladder mucosa caused by chitosan dispersions, a well-established, cationic, mucoadhesive polymer, which increased the permeability of isolated pig bladder to a model drug by causing desquamation of the urothelium (27)(28)(29)(30).…”

Drug delivery system based on dendritic nanoparticles for enhancement of intravesical instillation

“…[27][28][29] However, the toxicity of chitosan to normal cell due to its highly positive charge is a big concern for further clinical application. 30 Therefore, we evaluated the biocompatibility of PAMAM. As shown in the Results section, PAMAM, without any surface modification, showed significant toxicity to both normal urothelial cells and bladder cancers (Figure 3), which is consistent with the previously reported results.…”