构建生物可降解性复合支架修复腹壁缺损的可行性研究

目的:探讨采用聚乳酸(polylactic acid,PLA)、甲壳素与明胶为原料,构建生物可降解性复合支架,修复腹壁缺损的可行性。方法:采用1%戊二醛交联的明胶作为支架内芯,PLA和甲壳素以7∶1比例纺丝编织构建支架的外网套,将明胶嵌入外网套,以构建生物可降解性复合支架。将支架浸于磷酸盐缓冲溶液(PBS)中震荡,以检测支架的降解时间;采用直接接触和MTT法检测支架的细胞毒性;通过拉伸、胀破实验测定其力学性能;将密度为1×107/mL的成纤维细胞种植至支架上,观察细胞的黏附、增殖、分化及基质分泌情况。结果:交联明胶的降解时间为(54.8±0.5)d,可适应在细胞长入后的早期降解。外网套的降解时间为(312.5±6.5)d,可维持较长时间的力学强度;横向断裂强度为(319.2±37.8)N,纵向断裂强度为(620.4±45.2)N,可以满足修复腹壁缺损的力学要求。细胞毒性实验显示支架细胞毒性为0～1级,增殖良好;与未交联组(对照组)相比,无统计学差异(P0.05)。成纤维细胞种植在支架上培养5 d后长满支架表面;细胞种植7 d后,开始分泌胞外基质。结论:由交联明胶作为内芯,PLA及甲壳素编织物作为外网套构建的生物可降解性复合支架具有良好的机械性能、降解性、生物相容性,体外实验结果证实其可满足腹壁缺损修复的要求。

The feasibility of repairing abdominal wall defects by designed biodegradable composite scaffold

Objective This study is designed to investigate the feasibility of repairing abdominal wall defects by biodegradable composite scaffold constructed by us with polylactic acid,chitin and gelatin.Methods Natural gelatin was cross-linked through 1% glutaraldehyde as the internal biodegrad-able scaffold.Polylactic acid was mixed with chitin in the ratio of 7∶1 to fabricate the external mesh.Then,the gelatin mesh was inserted into the external mesh.The degradation time of the scaffold was observed through immersion into the PBS solution.Direct contact and MTT were used to detect the cytotoxicity;mechanical properties were measured through stretching and bursting load tests,cell adhesion,proliferation,differentiation and collagen secretion status were observed by seeding 1×107 cell/mL fibroblasts on the scaffold.Results The degradation time of cross-linked gelatin was（54.8±0.5） days,which could meet the demands of early degradation after cell ingrowth.The degradation time of external mesh was（312.5±6.5） days,which could help maintaining long-term strength during tissue regeneration.The transversal fracture strength of the external mesh was（319.2±37.8）N,and its vertical fracture strength was（620.4±45.2）N,both were adequate for abdominal wall defects repairing.Cytotoxicity test of the scaffold demonstrated that it belonged to grade 0-1;and the fibroblasts proliferated well on the scafold;there was no statistically significant difference as compared with the control group（P0.05）.The scaffold had been covered fully by fibroblasts after seeding and mixed culturing for 5 days.Light microscope showed that the fibroblasts started secreting extracellular stroma from the 7th day.Conclusions We applied cross-linked gelatin as the internal scaffold and fabricated polylactic acid-chitin mixture as the external mesh to construct the biodegradable composite scaffold.The scaffold is totally degrable and biocompatible.Furthermore,it possesses good mechanical properties.The properties of the scaffold in vitro meet the requirements for usage in repairing abdominal wall defects.