BACKGROUND:Aortic root homograft has been widely used, but it stil has a high incidence of calcification and degeneration after operation. OBJECTIVE:To investigate the alteration of biological and immunological properties of rabbit aortic root homograft treated with de-endothelialization and decellularization methods, and to find a better decellularization method. METHODS:Aortic root homografts obtained from rabbits were randomly divided into fresh group, de-endothelialization group, and decellularization group. The morphology of homografts was evaluated by hematoxylin-eosin, Masson and VG stainings. The biological properties such as thickness, tensile strength, broken extension rate, and heat shrinkage temperature were detected. The immunological features (inflammatory cellinfiltration, calcium content and CD152 expression) were determined with immunohistochemistry and flame atomic absorption spectrometry. RESULTS AND CONCLUSION:As demonstrated in morphological observation, protocols of de-endothelialization and decellularization methods we used attained our desired aim of decellularization perfectly. Tensile strength and broken extension rate of decellularization group were decreased significantly compared with fresh group (P<0.01), while the difference between de-endothelialization group and fresh group was not significant (P>0.05). Hematoxylin-eosin staining showed that, inflammatory reaction was the most apparent in fresh group, showing a large amount of inflammatory cells infiltration;compared with fresh group, inflammatory reaction was significantly attenuated in de-endothelialization group, the number of inflammatory cells was significantly decreased. The inflammatory reaction was the lowest in the decellularization group, only inflammatory cells infiltrated the tissue edge. Immunohistochemistry showed that, CD152 expression was significantly increased in de-endothelialization and decellularization groups compared with fresh group (P<0.05). Calcium content in de-endothelialization and decellularization groups was significantly decreased compared with fresh group (P<0.05). It could be concluded that the immunogenicity of de-endothelialized and decellularized aortic homografts is decreased significantly, and the de-endothelialization method could better maintain the tensile property.%背景：目前同种瓣已在临床广泛应用，但移植后远期易发生衰败和钙化。 目的：探究同种带瓣主动脉经去内皮和去细胞处理后，生物学特性和免疫原性的变化，寻找更好的同种瓣去细胞处理方法。 方法：取家兔带瓣主动脉根部，随机分为新鲜组、去内皮组、去全部细胞组。分别采用苏木精-伊红、Masson、VG染色进行组织形态学观察；生物学特性评价组织厚度、抗张强度、断裂拉伸率、热皱缩温度；通过免疫组织化学染色观察及原子火焰吸收法测定移植物钙含量变化进行免疫原性评价。 结果与结论：组织形态学观察发现去内皮和去细胞方案均达到了对应的去细胞目的。与新鲜组相比，去内皮组抗张力性能变化不明显(P>0.05)，去细胞组显著下降(P<0.01)。异体移植实验后苏木精-伊红染色观察发现：新鲜组炎性反应最为显著，组织中有大量炎细胞浸润；与新鲜组相比，去内皮组炎性反应明显减轻，炎性细胞数目明显减少，去细胞组炎性反应最轻，仅组织边缘有炎性细胞浸润。免疫组织化学发现：去内皮组和去细胞组CD152表达水平明显高于新鲜组(P <0.05)。钙含量分析发现：去内皮组和去细胞组钙盐含量较新鲜组显著下降(P<0.05)。提示去内皮和去细胞同种带瓣主动脉的免疫原性均显著下降，而去内皮处理能更好地保留同种瓣的抗张性能。
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