Transplantation Of Amniotic Scaffold Seeded Bone Marrow MSCs And/or EPCs To Repair Long Tubular Urethral Defect In Dogs

Currently, the therapeutic strategy of tubular urethral defect has not yet been obtained.But tissue engineering show the most promising effect in repairing urethral defect. However how to promote tissue regeneration and angiogenesis is still in solving. In order to solve the problem. Freezing and thawing- sodium dodecyl sulfate(SDS)- nucleic acid enzyme method was used to prepare decellularized human amniotic scaffold(dHAS), and then seeded bone mesenchymal stem cell(BMSCs) and EPCs on dHAS. Finally, the cell-free result of dHAS and the compatibility of dHAS with BMSC and EPCs were evaluated by haematoxylin-eos staining(HE) and scanning electron microscope. After that, 25 male mongrel dogs chose and prepared 3 cm urethral defect model, and then, the urethral defect models were repaired with MSCs+EPCs-seeded dHAS(BMSCs+EPCs group), EPCs-seeded dHAS(EPCs group),BMSCs-seeded dHAS(BMSCs group), blank dHAS(dHAS group) and nothing(control group). The effect of urethral reconstruction was estimated by urination observation after surgery, urethrography proceeded at 4, 8 weeks, urethral anatomy check and histological analysis at two months after surgery. The results are as follows:1. The amnion cells were removed completely. The surface of dHAS likes a fiber mesh.After seeded and cultured BMSCs and EPCs on the dHAS, the cells were adhered on dHAS equably.2. A normal urethrogram were observed in BMSCs+EPCs group and EPCs group except a diverticulum was found in one dog of EPCs group. Progressive stenosis was found in BMSCs group, dHAS group and control group, but the length of stricture was shortest in BMSCs group and longest in control group. Histological observation showed that multilayered columnar epithelium formed in BMSCs+EPCs group and EPCs group, which was distinct from BMSCs group, dHAS group and control group. The surface of stricture urethra was covered with 1-2 layers epithelial in BMSCs group and dHAS group. However in control group, almost no epithelial cells growth was observed. Regenerative submucosal tissue of BMSCs+EPCs group was rich in sinusoids. EPCs group has less sinusoid than normal. In the BMSCs group, dHAS group and control group, the regenerative submucosal tissue was lack of sinusoids and structure disturbance.In summary, we have succeeded in preparing dHAS and repairing canine 3 cm tubular urethral defect by transplant dHAS with BMSCs and EPCs or EPCs, but the effect was better with BMSCs and EPCs.