(A) Without injury, the luminal surface of the bladder exhibited the well-characterized polyhedral morphology with ridges that demarcate cell boundaries (blue lines and arrows; ref. 15). At 7 hours after injury, however, the surface morphology was drastically altered, with loss of the characteristic junctional ridges. By 2 days postinjury (dpi), umbrella cells were regenerated, but they were smaller in size than those without injury, although they established polyhedral morphology (red arrows). (B) With intravesical instillation of LM11A-31 immediately after SCI, however, umbrella cell loss was completely blocked, with intact polyhedral ridges at both 7 hours and 2 days after injury (blue lines and arrows). (C) At 7 hours after injury, the luminal surface of the bladder from p75^KO mice was visually indistinguishable from that of the control bladder. Blue dotted lines mark the hexagonal boundaries of umbrella cells. Higher-magnification images illustrate the cell boundaries between neighboring cells (arrows). (D) H&E staining of the control and LM11A-31–treated bladders. Note the preservation of the urothelium at 1 day after injury with LM11A-31, while very few urothelial cells are visible in vehicle-treated bladder. LM11A-31 also prevented chronic urothelial hyperplasia and detrusor hypertrophy of the bladder at 10 days after injury. The bladder morphology appears similar to that of the uninjured control bladder. Urothelial and muscle layers of the bladder wall are indicated by U and M, respectively, and the bladder lumen is indicated by L. Scale bar: 250 μm. Experiments were performed 3 times, and representative ones are shown.