Electrospun PLGA and PLGA/gelatin scaffolds for tubularized urethral replacement: Studies in vitro and in vivo

To investigate the biocompatibility of polylactic acid-glycolic acid copolymer (PLGA) and PLGA/gelatin scaffolds and their suitability for tubular urethral replacement in a canine model. PLGA and PLGA/gelatin scaffolds was constructed by electrospinning. Microstructural differences between the scaffolds was examined by Scanning electron microscopy (SEM) followed by mechanical properties testing. Biocompatibility of the material was evaluated using SEM 4, 8, 12 and 72 h after PLGA and PLGA/gelatin scaffolds co-culture with urothelial cells. And confocal analysis was also used to showed the cell adhesive and growth at 12 h. Approximately 2 cm of the anterior urethra of twelve dogs were removed and replaced with a scaffold. After the surgery for 1 month performed urethrography and for 3 month perform hematoxylin-eosin (H&E) and Masson. The results indicated that PLGA and PLGA/gelatin scaffolds had a void microfilament structure, similar to that of normal acellular matrix tissue. And the tensile strength was decreased whereas the tensile deformation and suture retention strength was increased in PLGA/gelatin scaffolds compared to that in PLGA scaffolds Urothelial cells grew well on both scaffolds. Postoperatively, animals recovered well and urinated spontaneously. However, urethrography showed varying degrees of urethral strictures in the reconstructed urethras. H&E and Masson showed that multilayer urothelial cells were formed in both the proximal and distal segments of the reconstructed urethras but without continuity. There was a small amount of smooth muscle and blood vessels under the epithelium, but regenerative urothelial cells at the midpoint of the reconstructed segment did not continue. Lots of lymphocyte infiltration was observed under the epithelium, some collagen tissue was deposited under the neo-urethral epithelium were observed. In conclusion, PLGA and PLGA/gelatin scaffolds are not suitable for tubularized urethral replacement in the canine model.