Intravesical application of rebamipide promotes urothelial healing in a rat cystitis model.

Rebamipide is used as a topical therapeutic agent for various organs. We examined the healing effects of intravesical rebamipide on damaged urothelium in a rat model of chemically induced cystitis. Hydrochloride was injected in the bladder of female Sprague Dawley® rats to induce cystitis. On days 1 and 4 rebamipide (1 or 10 mM) or vehicle was administered in the bladder and maintained for 1 hour. Histopathology, urothelial permeability, cystometrogram and nociceptive behaviors were evaluated on day 7. Also, tissue rebamipide concentrations after the 1-hour bladder instillation were quantified using high performance liquid chromatography. Intravesically administered rebamipide permeated the bladder, particularly in hydrochloride treated rats, and the pharmacologically effective tissue dose remained for greater than 6 hours. Bladder histological evaluation revealed polymorphological inflammatory cell infiltration and decreased positive staining for uroplakin 3A in hydrochloride treated rats. Scanning electron microscopy showed damaged tight junctions in the hydrochloride group. Evans blue absorption in the bladder wall was increased in hydrochloride treated rats. These findings, which were associated with urothelial injury and increased permeability, were dependently suppressed by the rebamipide treatment dose. Cystometrogram demonstrated that the intercontraction interval was shorter in hydrochloride treated rats but prolonged by rebamipide. The increased nociceptive behaviors observed after intravesical resiniferatoxin administration were also suppressed by rebamipide. Intravesical rebamipide accelerated the repair of damaged urothelium, protected urothelial barrier function and suppressed bladder overactivity and nociception.