PLGA/ECM神经支架性质的体外评价

Analysis of an acellular pigskin based nerve scaffold

摘要:

以赖氨酸、神经生长因子 (NGF)、聚乳酸聚羟基乙酸共聚物 (PLGA)、猪皮来源的细胞外基质 (ECM) 为原料制备了一种复合材料；考察其内部三维结构，生物力学性质，降解特性，雪旺氏细胞黏附状况，以及其对NGF的可控释放作用；从而评价其作为促周围神经损伤修复支架的可行性。扫描电子显微镜 (SEM) 观察显示，PLGA渗透入去细胞猪皮内部固有的蜂窝状孔隙中，并覆盖在孔隙内表面；孔隙率为68.3％~81.2％，密度为0.62~0.68 g/cm3。复合材料的断裂强度为8.308 MPa，断裂伸长率为38.98％，弹性模量为97.27 MPa；在4周的体外降解测试中，其最大失重率为43.3％；赖氨酸在复合材料中的添加对降解液pH的相对稳定具有显著作用；在30 d中，复合材料对NGF的累积释放率为38％；通过雪旺氏细胞与复合材料的共培养，发现雪旺氏细胞能够在其表面及孔隙中黏附。因此表明本复合材料有望成为一种新型的促周围神经损伤修复支架。

Abstract:

A scaffold fabricated with lysine/nerve growth factor (NGF)/poly (lactic acid coglycolic acid) copolymer (PLGA) and acellular pigskin was evaluated in vitro as a potential artificial nerve scaffold. Properties of the scaffold such as microstructure, mechanical property, degradation behavior in PBS and water, Schwann cell adhesion property, and release of NGF were investigated. Results showed PLGA had permeated into the porous structure of acellular pigskin; its breaking strength was 8.308 MPa, breaking extensibility was 38.98%, elastic modulus was 97.27 MPa. The porosities of the scaffold ranged from 68.3% to 81.2% with densities from 0.62 g/cm3 to 0.68 g/cm3. At 4 weeks of degradation in vitro, maximum mass loss ratio was 43.3%. The release of NGF could still be detected on the 30th day, and its accumulative release rate was 38%. Lysine added into the scaffold neutralized the acidoid preventing degradation of PLGA to maintain a solution pH value. Schwann cells had grown across the scaffold after co-cultivation for 15 days. These in vitro properties of the pigskin based composite might indicate its potentiality to be an artificial nerve scaffold.