Making a Hydrophilic Interfacial Scaffold with Hierarchical Nanofibre Architecture to Enhance the Phenotypic Expression of Epithelial and Smooth Muscle Cells for Urethral Reconstruction

The repair and regeneration of tissues using tissue-engineered scaffolds represent an ultimate goal of regenerative medicine. Despite rapid developments in the field, urethral tissue engineering methods are still insufficient to replicate natural urethral tissue because the bioactivity of existing scaffolds is inefficient, especially for large tissue defects, which require large tissue engineering scaffolds. Here, we describe the efficiency of gelatine-functionalized, well-layered tubular nanofibre scaffolds of poly (L-lactic acid) (PLLA) in regulating the phenotypic expression of epithelial cells (ECs) and smooth muscle cells (SMCs) for urethral reconstruction. Flexible PLLA/gelatine tubular scaffolds with hierarchical nanofibre architecture were fabricated by electro-spinning. Compared with pure PLLA nanofibres, PLLA/gelatine nanofibres exhibited enhanced hydrophilicity and mechanical flexibility, significantly promoted the adhesion, oriented elongation, and proliferation of New Zealand rabbit autologous ECs and smooth SMCs simultaneously, and upregulated the expression of epithelial protein (AE1/AE3) in ECs and contractile protein (α-SMA) in SMCs as well as their synthesis of elastin. Three months of in vivo scaffold replacement of New Zealand rabbit urethras indicated that an engineered PLLA/gelatine tubular scaffold rich in seed cell-matrix bio-interface maintained urethral patency and facilitated oriented SMC remodelling, lumen epithelialization and angiogenesis. Our observations showed the synergistic effects of nano-morphology and biochemical clues in the design of biomimetic scaffolds, which can effectively promote urethral regeneration. Funding Statement: This study was financially supported by the National Natural Science Foundation of China (No.81771629 and No.81900619), 2013 National Clinical Key Specialist Construction Project (pediatric surgery) (No.5001-2140019) and Postdoctoral Science Foundation of China (No.2018M630936). Declaration of Interests: The authors declare no competing financial interest. Ethics Approval Statement: This animal experimental protocol was approved by the animal experimentation Ethics committee, the Guangzhou Medical University.