Introduction

We showed that both injections and cell sheets of isolated single bone marrow-derived cells could restore structures and functions of radiation-injured urinary bladders. However, they had some limitations. Thus, we biofabricated bone marrow-derived cell patches with a bio 3-dimentional printer, Regenova (Cyfuse Biomedical K.K., Tokyo, Japan). We determined if the patches could restore structures and functions in the irradiated urinary bladders.

Methods

Twenty-four female 10-week-old Sprague-Dawley (SD) rats were irradiated with 2 gray once a week for 5 weeks. Bone marrow cells harvested from six male 17-week-old green fluorescence protein-transfected SD rats were cultured on collagen-coated dishes and flasks. The cultured bone marrow-derived cells were placed into U-type 96-well plates (3.0-5.0x10^4cells/100?l/well) to form spheroids. The spheroids were located on 9x9 arrayed needles of 4 mm square, and then it was accumulated with 3 layers. The accumulated spheroids were cultured in the perfusion chamber. After 7 days, the fused structures (patches) were pulled out from the needles. Each patch was transplanted into the irradiated anterior bladder wall (n=10). As controls, sham operations were performed (n=14). After 4 weeks, the urinary bladders were analyzed.

Results

In cystometric investigations, voiding interval and micturition volume in the patch-transplantation group were higher than those in the control group. Residual volume of the patch-transplantation group was lower compared to the control. At 4 weeks after, the transplanted patches detected on the bladder walls were organized into the recipient bladders (Fig.1A), and had blood vessels derived from the recipient tissues. In addition, there were many differentiated smooth muscle cells within the patches (Fig.1B-D). The chub-transplanted bladders reconstructed smooth muscle layers and nerve fibers.

Conclusions

The biofabricated bone marrow-derived cell patches could reconstruct structures and improve bladder functions in the irradiated urinary bladders.

Funding

None