改性聚乙二醇水凝胶在组织工程心脏瓣膜中的应用研究

Research on application of modified polyethylene glycol hydrogels in the construction of tissue engineered heart valve

目的探索改性聚乙二醇（PEG）水凝胶在改善种子细胞和去细胞生物材料支架的复合中的效果。方法猪主动脉瓣进行去细胞处理后分两组（n=8），A组：山羊自体骨髓间充质干细胞（BMSCs）作为种子细胞包裹于改性PEG水凝胶中贴附于去细胞猪主动脉瓣；B组：单纯种植BMSCs于去细胞猪主动脉瓣；并随机取两组中的8只山羊自身主动脉瓣为对照组（C组）。A、B组静态培养7d后，植入细胞供体羊的腹主动脉内；16周后取材进行形态学、组织学、B超、扫描和透射电镜观察以及生物力学检测。结果在张力强度[（12．9±1.3）MPa对（8．8±0．4）MPa]、内皮细胞覆盖率（84．6％对14．8％）、附壁血栓形成率（0／8对8／8）等方面A组明显优于B组（P〈0．05）。生物力学强度A组和C组差异无统计学意义。BMSCs于体内微环境下向内皮细胞和肌成纤维细胞分化。结论利用改性PEG水凝胶复合去细胞生物支架材料以及自体间充质于细胞构建组织工程瓣膜具有可行性。它可进一步改善种子细胞和支架材料之间的复合关系，并保护种子细胞在动脉流环境下的生长和分化。

Objective To explore the effect of the polyethylene glycol （PEG）-hydrogels to enhance the seeding-cells adhesion to the biomaterial scaffolds. Methods Sixteen porcine aortic valves were deeellularized with Triton X-100 and trypsin, then divided into A and B group, eight in each group. Group A： the donor goat＇s autologous bone marrow mesenehymal stem cells （BMSCs） Selected as the seeding-cells were encapsulated into the modified PEG-hydrogels to complete the process of the cells attaching to the acellular porcine aortic valves. Non-PEG but reservation of BMSCs was modified in Group B. After static culture for 7 d, the mono semilunar tissue engineering heart valve （TEHV） were implanted respectively into each donor goat＇ s abdominal aortas. Gross and histology examination, ultrasonic scanning, electron microscopy observation and biomechanies detection were performed at 16 weeks after operation. The 8 native goat aortic valves from the donor goats were selected at the same time as control group（ Group C ）. Results There were much more improvements compared Group A to Group B （P 〈 0. 05 ） in tensile strength [（12.9±1.3） MPavs. （8.8±0.4） MPa], ratio of reendothelial （84.6% vs. 14.8%） and mural thrombosis （0/8 vs. 8/8 ）. The data illustrated the critical importance of BMSCs differentiation to endothelial and myofibroblast for remodeling into native tissue in microenvironment in vivo. Conclusions It is feasible to reconstruct TEHV efficiently by combining modified PEG-hydrogels with aeelluar biomaterial scaffold and autologous MSCs cells. It can improve the integration of the seeding-cells and scaffold. It can also protect the growth and differentiation of the BMSCs in the systemic circulation effectively.