2b). Immunohistochemistry also shows that the sham-injured urethral sphincters are composed of distinct muscle tissues containing numerous myoglobin- (Fig. 2c) and SMA-positive cells (Fig. 2d). In contrast, the

7-day-old freeze-injured internal urethral orifices appear to be relaxed, creating a larger orifice (Fig. 2e). The injured urethral sphincters show reactive changes, including loss of muscle mass and relative disorganization of the remaining muscle tissues (Fig. 2e). Accompanying these changes is the loss of the majority of the striated and smooth muscle cells (Fig. 2f) and the absence of most myoglobin- (Fig. 2g) and SMA- positive cells (Fig. 2h). These findings of induced ISD-related urinary incontinence are similar to other models of urinary incontinence4,48–50 with respect to loss of striated and smooth muscle and reduced leak point

pressures. The Selleck U0126 urinary sphincters of patients with post-surgical urinary incontinence are irreversibly damaged. However, this appears not to be the case in our model system. The cell-free injected control rabbits show a weak but natural Selleck CH5424802 recovery of striated and smooth muscle cells that is accompanied by a slight increase in leak point pressure. These results are not entirely surprising. Rabbits may have inherently different regenerative powers than humans. Additionally, and of possibly greater importance, the rabbits are young and in good health, in contrast to patients with ISD-related urinary incontinence, who are typically elderly and not in

good general health. In our rabbit model, we intentionally avoided more severe and serious sphincter damage that would have produced irreversible incontinence because of the potential for urethral stricture or perforation, followed by death. Thus, our model is considered to be an filipin acute incontinence of relatively short duration. Ten days after harvesting the bone marrow cells and placing them in culture, and 7 days after freeze-injury operation, we divide the rabbits into cell implantation and cell-free injection control groups.3 For the cell implantation group, we implant the 0.5 × 106 autologous bone marrow-derived cells suspended in 100 µL culture medium. A total of 2.0 × 106 cells are injected through a 29-gauge syringe needle into the injured regions at the 3-, 6-, 9-, and 12-o’clock positions. For the cell-free injection control group, we similarly inject 100 µL of cell-free culture medium. The number and volume of the implantation cells are chosen to avoid further damaging the host tissues or the implanted cells due to shear stress. At each operation, the retention of small swellings containing the implanted cells or control media is visually confirmed. At 7 days after cell implantation, the leak point pressure of the cell-implantation group, 13.15 ± 2.