Alteration of biological and immunological properties of aortic homografts after de-endothelialization and decellularization / 中国组织工程研究

ABSTRACT

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 (P0.05). 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.