构建具有良好结构与功能的支架，为种子细胞提供理想的生长微环境，同时有效抑制尿道瘢痕的形成，是组织工程尿道重建的关键。天然的细胞外基质支架，其生物相容性虽较佳，但力学强度不足。我们前期研究发现纳米纤维其特有的高比表面积，高孔隙率，高渗透性可最大程度的模仿细胞外基质的天然结构，生物相容性佳，且可调控其强度，易形成产业化。转化生长因子-β1（TGF-β1）被认为是重要的促瘢痕形成因子。我们前期研究显示通过抑制TGF-β1表达，可减少胶原合成，促进其降解，防止瘢痕的形成。故本研究拟采用聚己内酯/胶原/丝素蛋白新型纳米纤维为支架，以口腔黏膜细胞和成纤维细胞为种子细胞，在此基础上，以siRNA干扰技术，抑制成纤维细胞TGF-β1表达，使构建的纳米组织工程尿道可有效抑制瘢痕的形成。以期探寻尿道重建的新策略，降低尿道狭窄的复发率，为纳米组织工程尿道重建技术的进一步研究和临床应用提供理论基础和实验依据。

The key of urethral reconstruction with tissue engineering is to prepare the scaffold with good structure and function which could provide an ideal growth microenvironment for seed cells and inhibit the formation of urethral scar. The extracellular matrix scaffolds don't have adequate mechanical strength, although its biocompatibility is good. In our previous study, we found that the nanometer fiber could mimic the extracellular matrix in the greatest extent because it has a high specific surface area, a high porosity, a high permeability and excellent biocompatibility. And it is easy to control the intensity form the industrialization. Transforming growth factor - β 1 (TGF- β1) is considered to be the important factor promoting scar formation. In our preliminary study, it showed that the down regulation of fibroblasts synthesis type I collagen and inhibition of scar formation could be achieved by constructed siRNA interfering TGF-β1 expression. We plan to adopt polycaprolactone / collagen / silk fibroin nanofibers as a scaffold, oral mucosa cells and fibroblasts as seed cells, to inhibit the expression of TGF-β1with siRNA interference technology, so that we can build the nano tissue engineering urethra which can effectively inhibit scar formation. This experimental study will explore the new strategy for urethral reconstruction and provide the theoretical basis and experimental basis for the clinical applications of nano tissue engineering techniques.