Experimental Study On Tissue-engineeringed Vascular Model In Vitro

Tissue engineering is the product of co-development and combination of modern cell biology, biomaterial science, and engineering. The aim of tissue engineering is to investigate and restore tissue and organ substitutes. The establishment of tissue engineering technique means that human beings will be out of the era of tissue and organ transplatation, and step into the new era to restore tissue and organ. A best substitute of blood vessel has been pursued for a long time. Many materials have been tried such as autogenous artery or vein, artif icial material, biomaterial and et al, but no ideal substitute was found until now. Tissue engineering is a new and rapidly expanding field ,in which a series of techniques are being developed for culturing and reconstructing a variety of tissues both in vitro and in vivo. Using those techniques, it is possible to reconstruct vascular model in vitro whose structure and function are same as autogenous vessels.In this experiment two degradable materials were precoated with cross-linked type I collagen, moulded into tubular porous scaffold, and then seeded with ECs. Using rotary cell culture technique, vascular model wasconstructed in vitro. Part IObjective: To provide cells resource for the experimental study on vascular tissue engineering. Methods: Vascular endothelial cells , smooth muscle cells and fibroblast are respectively isolated from human umbilical veins by enzyme digestion and tissue plant methods, subcultured, purified and identified, etc. Phase-contrast and electron microscopy was used to analyze the cells morphological characteristics. Results: the morphological characteristics of three kinds of cells are accord with those of vascular endothelial cells , smooth muscle cells and fibroblast. Conclusion: The cultured cells can meet the experimental expectations on vascular tissue engineering. Part IITubular porous vascular scaffolds were constructed . PGA, PHB meshes were dipped into cross-linked type I collagen solution, dried under vacuum freeze condition in a special annular model. The tubular porous scaffolds have elasticity, tenacity and hydrophilic, can maintain their shapes in culture medium for long time.A rotary cell culture system was designed, which was composed of micromotor, rotate part, gear part and et al. In this system, tubular scaffold can rotate slowly around own major axis. By means of this, three-dimension tissuesor organs can be cultured in vitro. Part IIIHVEC, VSMC and fibroblast were seeded onto inner surface of tubular porous PGA and PHB scaffold precoated with collagen. Sead HVEC,VSMC and fibroblast onto three porous polyglycolic acid and Poly- ?-ydroxybutyrate scaffolds precoating with collagen, which different caliber but embedded each other. Observe cell growth and differentiation on these scaffolds. 3 rd-7 th passages of HVEC, VSMC and fibroblast were seeded onto these materials, cultured in vitro for 3 weeks using dynamic rotation culture technique. Scanning election microscopy was used to anayse. RESULT: The layers of tissue engineeringed vascular model were combined tightly. HVEC, VSMC and fibroblast can secrete extracelluar matrix(ECM) and interchange substance, resemblin physiological functions. CONCLUSION: Tubular porous PGA and PHB precoating with collagen can be used as scaffold for constructing vessel in tissue engineering .This will be good foundation for architecture of a layered structured vessel in next stage.