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目的 对去细胞猪主动脉瓣膜进行聚乙二醇(PEG)化改性,并评价改性后复合支架的细胞毒性.方法 合成功能基团为丙烯酰基的枝化状聚乙二醇衍生物,在去细胞猪主动脉瓣膜引入巯基,通过迈克尔加成反应完成PEG对去细胞猪主动脉瓣膜的交联,并作PEG改性前后瓣膜的生物力学测定.制作去细胞瓣膜的浸提液,浸提液分为单纯去细胞瓣膜组、PEG改性去细胞瓣膜组和阴性对照组(培养液),采用CCK-8法检测复合支架的浸提液对人脐静脉内皮细胞增殖率的影响,评价其细胞毒性.结果 PEG改性去细胞瓣膜反应条件温和,改性效果确切.复合瓣膜支架的抗拉强度明显高于去细胞瓣膜[(7.53±0.29)MPa比(5.65±0.24)MPa,P＜0.05],但与天然瓣膜[(7.68±0.20)MPa]差异无统计学意义(P＞0.05).复合支架和去细胞瓣膜毒性评级均0级,与阴性对照组差异无统计学意义(P＞0.05).人脐静脉内皮细胞经各浸提液的培养液培养后形态良好,增殖旺盛.结论 PEG改性能明显改善去细胞猪主动脉瓣膜的力学性能,且改性后的复合支架无细胞毒性,为进一步研究提供依据.

Objective To modify acellular porcine aortic valve scaffolds using polyethylene glycol (PEG) and to assess their cytotoxicity in vitro. Methods Dendritic PEG derivatives with acryloyl functional group were synthesized followed by introduction of thiol groups into acellular porcine aortic valves and cross- linking with PEG via Michael addition reaction.The biomechanical properties prior to and after PEG modification were compared.The extracts were divided into three groups:decellularized valve group,PEG - modified decellularized valve group, and control group (RPMI 1640 medium ).The impact of composite scaffolds extractant on human umbilical vein endothelial cells proliferation and in vitro cytotoxicity were assessed based on CCK - 8 assay.Results Modification of acellular porcine aortic valves using PEG occurred under mild reaction conditions and showed well-defined outcomes.Composite valve scaffolds had a markedly higher stretch- proof capacity than acellular porcine aortic valves [ (7.53±0.29) MPa vs (5.65±0.24) MPa,P＜0.05] but did not differ statistically from natural valves [ (7.53 ±0.29)MPa,P＞0.05].Cytotoxicity of composite scaffolds and acellular porcine valves were both graded as zero.Human umbilical vein endothelial cells cultured with medium containing composite valve scaffold extractants appeared in normal morphology and active proliferation.Conclusion PEG modification significantly improves the mechanical properties of acellular porcine aortic valves and reduces the cytotoxicity of composite scaffolds,thereby providing prospects for further researches.