天然及合成尿道重建支架材料的生物相容性及力学性能

背景：目前应用何种尿道组织工程修复重建支架材料更为合适的争论仍不断出现，其生物相容性及力学特性的评估也鲜见报道。 目的：评估应用于尿道修复重建多种生物材料的力学特性及生物相容性。 方法：脱细胞法制备小肠黏膜下层组织、膀胱脱细胞基质以及脱细胞尿道海绵体基质，同时编织法制备聚乙醇酸支架。单轴拉伸测试测定各类支架生物力学特性，光镜及扫描电镜测定支架表面孔径大小。线粒体代谢活性MTT法检测各种生物材料的细胞毒性。所有支架表面接种海绵体平滑肌细胞，体外培养14 d后进一步评估细胞渗透情况。 结果与结论：生物力学评估显示脱细胞尿道海绵体基质在弹性模量以及断裂强度方面的检测结果明显优于其余材料(P < 0.05)。MTT结果显示所有支架材料均支持正常的细胞生长代谢，并未发现存在明显的细胞毒性。聚乙醇酸在扫描电镜中显示出最大的孔径(> 200 μm)，同时脱细胞尿道海绵体基质的尿道面(< 5 μm)和海绵体面(>10 μm)观察到明显不同的孔径大小。细胞接种14 d后聚乙醇酸材料的内部可见种子细胞的广泛分布，在膀胱脱细胞基质以及脱细胞尿道海绵体基质的尿道面未发现有明显的细胞渗透迹象，而小肠黏膜下层组织和脱细胞尿道海绵体基质的海绵体面观察到明显的细胞渗透生长表现。提示所有支架材料显示出良好的生物相容性，同时在力学特性方面也与正常尿道组织相仿，但脱细胞尿道海绵体基质在力学和组织学的诸多参数上具有一定的优越性。

Biocompatibility and mechanical properties of naturally derived and synthetic scaffolds for urethral reconstruction

BACKGROUND:Recently debates on what kinds of urethral repair and reconstruction of tissue engineering scaffolds are more suitable occurred constantly, its evaluation of biocompatibility and mechanical properties are also poorly reported. OBJECTIVE:To evaluate the mechanical properties and biocompatibility applied to urethral repair and reconstruction of a variety of biomaterials. METHODS:Small intestinal submucosa (SIS), bladder acellular matrix graft (BAMG), and acellular corpus spongiosum matrix (ACSM) were prepared by decellularization method; polyglycolic acid (PGA) scaffold was prepared by knitting method. Uniaxial tensile mechanical testing was conducted to determine biomechanical properties of each scaffold; the surface pore size of scaffold was determined by light microscopy and scanning electron microscopy. Cytotoxicity of various biomaterials was detected by MTT assay. Corporal cavernosum smooth muscle cells (CCMSc) were inoculated in all scaffolds, cell permeability was further assessed after 13 days cultured in vitro.  RESULTS AND CONCLUSION:Biomechanical evaluation showed that the detection results of ACSM in terms of elastic modulus and fracture strength was prior to other materials (P < 0.05). MTT assay showed that all the scaffolds were in support of normal cell growth and metabolism without obvious cytotoxicity. PGA showed the largest pore size in the scanning electron microscope (> 200 μm); meanwhile, the ACSM has different pore sizes in urethral (< 5 μm) and corpus cavernosum surfaces   (> 10 μm). Widespread distribution of cells could be observed in PGA 14 days after seeding. There was no obvious sign of cell penetration in BAMG and ACSM urethral surfaces. However, significant cell penetration growth performances in cavernosal surfaces of SIS and ACSM were observed. It is indicated that all scaffolds demonstrated good biocompatibility, which is similar to normal urethral tissue in terms of mechanical properties. However, ACSM has certain advantages in many parameters of mechanics and histology.