Development of Bilayered Bone Marrow-derived Cell-Gelatin Grafts for Augmentation Cystoplasty and Reconstruction of Bladder Tissues in Rats

Background : This study attempted to produce a novel graft composed of bone marrow-derived mesenchymal cell (BMC) layer-gelatin sheets for bladder augmentation cystoplasty. Then, we determined if the grafts could reconstruct bladder tissues. Methods : BMCs harvested from the femurs of green fluorescence protein (GFP)-transfected Sprague-Dawley (SD) rats were adherent and proliferating cells on collagen dishes. The cells were then cultured on temperatureresponsive culture dishes. Following this, the BMCs maintaining cell-cell contacts within the monolayer itself were applied to a gelatin sheet. Two BMC layer-gelatin sheets were overlaid together with the cell sides juxtaposed with one another (bilayered BMC-gelatin graft). Bladder top of SD rats were incised and transplanted with the bilayered BMC-gelatin grafts. Similarly, urinary bladders irradiated with 2 Gy once a week for 5 weeks were also conducted. As control, bilayered acellular-gelatin grafts were used. At 4 weeks after transplantation, the bladders were histologically investigated. Results : At 4 weeks after transplantation into either normal or radiation-injured urinary bladders, incised regions closed. The closed regions of bladder top had reconstructed tissues that were formed with urothelium, and smooth muscle layers. Within the reconstructed tissues, the thickness of the smooth muscle layers in the bilayered BMC-gelatin graft-transplanted bladders were larger compared to controls. The GFP-positive transplanted BMCs were detected. Some of the cells were simultaneously positive for smooth muscle or nerve cell markers. Conclusion : This study showed that the bilayered BMC-gelatin grafts that were experimentally produced could reconstruct bladder tissues. The grafts would be developed as grafts for bladder augmentation cystoplasty.Article信州医学雑誌 71(3) : 167-177, (2023)journal articl