缓释脂肪干细胞外泌体的水凝胶纳米纱复合支架修复尿道缺损及其机制

It is an urgent need to solve the clinical problem of repairing long segmented urethral stricture and hypospadias. Tissue engineered urethra has been used in the study of urethral repair, however, currently used cells, scaffolds and the other elements still need to be improved. Our hydrogel and nanoyarn as tissue engineering scaffold in the initial study showed good biocompatibility, recently, we found the exosomes, obtained from adipose derived stem cells (ADSCs-Exo), contained many growth factors which could promote the growth of urothelial cells et al. Therefore, we plan to produce an ADSCs-Exo-hydrogel-nanoyarn composite scaffold, slowly-release ADSCs-Exos at urethral defect to promote the growth of urethral cells, in order to improve the effect of urethral repair. This study firstly detected cytokines and nutritional factors by protein chip, then add ADSCs-Exo to primary beagle urothelial cells, endothelial cells et al to observe the effect on cell proliferation. Finally, the ADSCs-Exo-hydrogel-nanoyarn composite scaffolds will be built to test the efficacy for urethral defect repair through the beagle urethral defect model. Completion of this task will provide experimental basis to clinical development of biological scaffold for urethral stricture or hypospadias treatment.

长段尿道狭窄和尿道下裂的修复是临床急需解决的问题，组织工程尿道已被应用于尿道修复研究，然而目前所用的细胞和支架等元素仍需改进。我们前期采用水凝胶和纳米纱作为组织工程支架材料，显示良好的生物相容性，最近，我们又发现比格犬脂肪干细胞（ADSC）分泌的外泌体（Exo）（ADSC-Exo）内含有很多生长因子，能促进尿路上皮细胞等的生长。因此，我们设想制作ADSC-Exo水凝胶纳米纱复合支架，在尿道缺损部位缓释ADSC-Exo，促进尿道细胞的生长，提高支架对尿道修复的效果。本研究首先采用蛋白质芯片检测ADSC-Exo的细胞因子和营养因子，然后在原代分离培养的比格犬尿道上皮、内皮等细胞中加入ADSC-Exo，观察对细胞的增殖作用。最后，构建ADSC-Exo水凝胶纳米纱复合支架，通过比格犬尿道缺损模型，检验复合支架对尿道缺损的修复作用。完成本课题将为临床开发尿道狭窄或尿道下裂治疗的生物支架提供实验基础

尿道狭窄和尿道下裂是泌尿外科的常见疾病，自体组织修复带来较大创伤，需要使用组织工程技术修复。我们进行了大量的研究探索，制备了多种生物材料用于尿道修复并进行了尿道狭窄相关机制的探索。1.制作了ADSC-Exo和纳米纱相互复合的生物材料，在尿道缺损部位缓释ADSC-Exo，促进尿道内相关细胞的生长，提高支架对尿道修复的效果。2.制作了负载Wnt通路抑制剂的纳米纱，在局部释放Wnt通路抑制剂，抑制尿道修复部位的疤痕增生；3.提取了犬尿道狭窄模型的疤痕组织，进行了miRNA测序，并进行了功能验证，4.我们将let-7i-5p基因在疤痕和正常成纤维细胞内过表达和抑制，证明let-7i-5p能够抑制成纤维细胞的迁徙，并且具有多种治疗尿道狭窄的作用。5.使用同轴共纺技术将外泌体负载于纳米纱内部，实现了尿道的生理性修复。6.在原代分离培养的比格犬尿道上皮、成纤维等细胞中加入ADSC-Exo，观察对细胞的增殖作用。7.使用纳米纱作为尿失禁治疗的尿道吊带材料，成功修复大鼠尿失禁模型。完成本课题将为临床开发尿道狭窄或尿道下裂治疗的生物支架提供实验基础。