骨髓间充质干细胞与尿道上皮细胞在尿道组织工程中的应用

Use of bone marrow mesenchymal stem cell and urothelial cell in urethral tissue engineering

目的比较分析骨髓间充质干细胞（bonemarrowmesenchymalstemcells，BMSC）与尿道上皮细胞作为种子细胞在尿道组织工程构建中的应用效果，为尿道组织工程构建的种子细胞筛选提供依据。方法分别体外培养兔BMSC及同种异体尿路上皮细胞，5-溴脱氧尿嘧啶核苷（BrdU）标记后接种至人真皮脱细胞基质。然后将体外构建的复合材料分别移植到尿道缺损动物模型体内，分别设为实验组A（BMSC组）和实验组B（尿路上皮组）。此外，将无细胞组（单纯的基质材料移植到尿道缺损处）作为对照组（C组）。于术后第1、2、4、12周分别采集尿道组织标本，行组织学观察。术后12周对实验动物行逆行膀胱尿道造影检查。结果第1周，A、B组均可见稀疏的单层上皮样细胞覆盖，但A组细胞形状较尿路上皮细胞组欠规则。第2周，A、B组仍是单层尿道上皮覆盖，但A组上皮细胞的致密度较差。第4周，A、B组上皮细胞分布与正常组织较接近，但BMSC组细胞分层较差。第12周，A、B组新生尿道与正常组织已无明显区分。4个观察点中，对照组的修复效果均比实验组差：A组术后并发症发生率为7．14％（2／28），B组为10．71％（3／28），C组为41．67％（5／12）。A组术前及术后12周排尿期最大尿道压检测值分别为（24．7±2．O）emilzO和（25．3±2．1）cmHzO，B组分别为（25．1±2．3）cmH20和（26．1±1．8）cmH2O，C组分别为（24．6±1．9）emil2O和（33．1±4．5）cmH：O。A、B两组手术前后最大尿道压比较，差异没有统计学意义（P〉0．05）；而C组手术前后最大尿道压比较，差异有统计学意义（P〈0．05）。结论BMSC或尿路上皮细胞复合脱细胞外基质移植到机体内均可有效修复尿道缺损；接种至第4周，发现尿路上皮细胞复合脱细胞基质材料修复尿道效果较BMSC好。

Objective To compare the uses of bone marrow mesenchymal stem cells （BMSC） and urothelium cells in urethral reconstruction and provide theoretical rationales for selecting urethral tissue engineering seed cells. Methods In experimental groups, we separated and cultured rabbit BMSC （group A） and urothelial cells （group ]3） in vitro and then seeded the cells labeled with bromodeoxyuridine in acdlular extracellular matrix. The composite matrix was planted into urethral segment of male rabbits. And urethral defect was repaired with acellular extracellular matrix in control group （group C）. Then urethral regeneration was observed at 1, 2, 4, 12 weeks postoperation respectively and the effects of reconstruction were evaluated by urethrography at 12 weeks. Results At 1 week, two experimental groups formed thin layer urothelium on repaired region. However, the cells of group A were less regularly arrayed than those of group B. At 2 weeks, two experimental groups were still covered by single urothelium cells, yet group B had a greater density of urothelium. At 4 weeks, the urothelium of two experimental groups was almost normal and the distribution of group A was better than that of group ]3. At 12 weeks, urothelium distribution in repaired region of each group was almost normal. And the effects of experimental groups were better than that of group C at all four observation sites. In group A, the postoperative rate of complications was 7. 14%（2/28） ; group B 10. 71%（3/28）;grouo C 41. 67% （5/12）. Groups A and B were more effectivelv repairedthan group C. The urethral pressure of preoperation and 12-week postoperation in group A was （24. 7 ± 2. 0） vs （25.3 ± 2. 1） cmH20（P〉0. 05） group B （25.1 ± 2. 3） vs （26. 1 ± 1.8） cmH20（P〉0. 05） and group C （24. 6 ± 1.9） vs （33. 1 ± 4. 5） cmH20（P〈0. 05）. Conclusions Both BMSC and urothelial cells seeded on acellular extracellular matrix can effectively repair urethral defect. Until Week 4 post- repairing, the effect of repair by urothelial cells-acellular extracellular matrix is better than that of BMSC.