Effects of human Muse cells on bladder inflammation, overactivity, and nociception in a chemically induced Hunner-type interstitial cystitis-like rat model.

INTRODUCTION AND HYPOTHESIS: We investigated the effects of locally administered human multilineage-differentiating stress enduring (Muse) cells, nontumorigenic pluripotent-like endogenous stem cells, on bladder tissues, function, and nociceptive behavior in a chemically induced Hunner-type interstitial cystitis (HIC)-like rat model without immunosuppressant. METHODS: Chemical cystitis was induced by intravesical instillation of 0.2 N hydrochloride (HCl) for 15 min in female F344 rats. SSEA-3+ Muse cells, SSEA-3- non-Muse cells or Hanks' balanced salt solution (HBSS; vehicle) were injected into the anterior and posterior bladder wall at each 1×104 cells/10 µl 6 h after HCl application. The sham group received HBSS without HCl instillation. Urinary frequency was assessed using metabolic cages, cystometrograms, nociceptive behavior, and histological analysis of the bladder and L6 spinal cord. RESULTS: Increases in urinary frequency and decreases in bladder capacity compared with the sham group were observed in the vehicle and non-Muse groups, but not in the Muse group, at 1 week. Significant increases in nociceptive behavior compared with the sham group and the expression of TNFα in the bladder and c-Fos in the bilateral dorsal horns of L6 spinal cord were also observed in the vehicle and non-Muse groups, whereas these changes were not seen in the Muse group at 1 week. Histological analysis exhibited a higher proportion of injected Muse cells remaining in the urothelial basal layer and lamina propria of the bladder than non-Muse cells until 4 weeks. CONCLUSIONS: Muse cell therapy could be a promising modality for treating HIC.