组织工程骨膜成骨的构建及血管化超微结构的观察

目的用组织工程方法构建组织工程骨,从超微结构观察成骨过程中成骨细胞、血管再生的变化,探讨小肠黏膜下层作为组织工程骨支架材料促进组织工程骨血管化的优越性。方法应用密度梯度离心法体外分离、培养骨髓基质干细胞,并将成骨诱导骨髓基质干细胞与小肠黏膜下层复合培养2周。未复合细胞的单纯材料作为空白对照。将复合培养细胞与单纯材料分别植入无胸腺裸鼠皮下,扫描和透射电镜观察植入前和植入后4、8、12周成骨细胞、血管生成的变化过程。结果体外复合培养见细胞在材料上生长、分化、增殖良好,细胞分泌大量的细胞外基质,置入体内后成骨良好,形成大量的血管;12周后材料被吸收,与周围组织无明显界限。单纯材料中央部位有大量小血管及血管内皮细胞增生,其周围多为成纤维细胞,无成骨细胞。结论小肠黏膜下层作为以骨髓基质干细胞为种子细胞的支架材料,有利于骨的再生和血管化形成,是一种良好的骨组织工程支架材料。

Ultrastructure of Vascularization During Osteogenesis by Tissue Engineering Technique

Objective To observe the changes of osteoblasts and vascularization during osteogenesis by tissue engineering technique under the electron microscope and study the feasibility of improving vascularization of the tissue engineering bone by using the small intestine submucosa(SIS) as the scaffold. Methods The bone mesenchymal stem cells(BMSCs) were isolated by using the gradient centrifuge method.BMSCs were seeded in the SIS.The scaffold-cell constructs were cultured in vitro for two weeks.There were no cells on the SIS as control.They were implanted subcutaneously in the dorsa of the athymic mice.The implants were harvested after(in vivo) incubation for 4,8 and 12 weeks.The changes of osteoblasts and vascularization were observed under the transmission electron microscope and the scanning electron microscope. Results The BMSCs grew quite well.BMSCs differentiated on the surface of the SIS and secreted a great deal of extracellular matrices.The scaffold-cell constructs formed a lot of bone and vessels in vivo.The scaffold degraded after 12 weeks.No osteoblasts but vascularization and fibroblasts were observed as control. Conclusion SIS can be used as the scaffold for constructing tissue engineering bone as it can improve the formation of bone and vessels in vivo.