Introduction and hypothesis: We investigated the effects of bladder wall injection of mesenchymal stem cells (MSCs) on bladder tissues, function, and nociceptive behavior in a chemically induced interstitial cystitis-like rat model.
Methods: Chemical cystitis of female rats was induced by intravesical instillation of 0.1 N hydrochloride (HCl) once a week for 2 weeks. Bladders were harvested 1, 2, 3, and 4 weeks after the second application for histological examination. Adipose-derived MSCs (HCl + MSCs) or phosphate-buffered saline (HCl + PBS) was injected into the bladder wall at the time of the second application of HCl. Histological examination, nociceptive behavior, and cystometrograms were evaluated 2 weeks after the injection compared with controls, which received instillation and injection of PBS into the bladder (sham + PBS).
Results: The number of mast cells and expression of tumor necrosis factor-α (TNF-α) and transforming growth factor-β (TGF-β) were significantly increased at 1 and 2 weeks, and expression of collagen fibers was significantly increased from 2-4 weeks after the second application of HCl. Significantly increased nociceptive behavior, number of mast cells, expression of TNF-α, TGF-β, and collagen fibers were observed in HCl + PBS compared with sham + PBS, whereas these changes were significantly decreased in HCl + MSCs compared with HCl + PBS. In addition, bladder capacity and voiding threshold pressures were significantly decreased in HCl + PBS but not in HCl + MSCs compared with sham + PBS.
Conclusions: The results suggest that bladder injection of MSCs ameliorates inflammation and fibrosis in bladder tissues, bladder overactivity, and nociception in a rat model of chemically induced cystitis.
Keywords: Adipose; Hydrochloride; Interstitial cystitis; Mesenchymal stem cells; Rats.