Liang Huang-Chien, Chang Yen, Hsu Cheng-Kuo, Lee Meng-Horng, Sung Hsing-Wen
Department of Chemical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC.
Biomaterials. 2004 Aug;25(17):3541-52. doi: 10.1016/j.biomaterials.2003.09.109.
It was reported that acellular biological tissues can provide a natural microenvironment for host cell migration and may be used as a scaffold for tissue regeneration. To reduce antigenicity, biological tissues have to be fixed with a crosslinking agent before implantation. As a tissue-engineering scaffold, it is speculated that the crosslinking degree of an acellular tissue may affect its tissue regeneration pattern. In the study, a cell extraction process was employed to remove the cellular components from bovine pericardia. The acellular tissues then were fixed with genipin at various known concentrations to obtain varying degrees of crosslinking. It was shown in the in vitro degradation study that after fixing with genipin, the resistance against enzymatic degradation of the acellular tissue increased significantly with increasing its crosslinking degree. In the in vivo subcutaneous study, it was found that cells (inflammatory cells, fibroblasts, endothelial cells, and red blood cells) were able to infiltrate into acellular tissues. Generally, the depth of cell infiltration into the acellular tissue decreased with increasing its crosslinking degree. Infiltration of inflammatory cells was accompanied by degradation of the acellular tissue. Due to early degradation, no tissue regeneration was observed within fresh (without crosslinking) and the 30%-degree-crosslinking acellular tissues. This is because the scaffolds provided by these two samples were already completely degraded before the infiltrated cells began to secrete their own extracellular matrix. In contrast, tissue regeneration (fibroblasts, neo-collagen fibrils, and neo-capillaries) was observed for the 60%- and 95%-degree-crosslinking acellular tissues by the histological examination, immunohistological staining, transmission electron microscopy, and denaturation temperature measurement. The 95%-degree-crosslinking acellular tissue was more resistant against enzymatic degradation than its 60%-degree-crosslinking counterpart. Consequently, tissue regeneration was limited in the outer layer of the 95%-degree-crosslinking acellular tissue throughout the entire course of the study (1-year postoperatively), while tissue regeneration was observed within the entire sample for the 60%-degree-crosslinking acellular tissue. In conclusion, the crosslinking degree determines the degradation rate of the acellular tissue and its tissue regeneration pattern.
据报道，脱细胞生物组织可为宿主细胞迁移提供天然微环境，并可用作组织再生的支架。为降低抗原性，生物组织在植入前必须用交联剂固定。作为一种组织工程支架，推测脱细胞组织的交联程度可能会影响其组织再生模式。在该研究中，采用细胞提取工艺从牛心包中去除细胞成分。然后用不同已知浓度的京尼平固定脱细胞组织，以获得不同程度的交联。体外降解研究表明，用京尼平固定后，脱细胞组织对酶解的抵抗力随交联程度的增加而显著增强。在体内皮下研究中，发现细胞（炎性细胞、成纤维细胞、内皮细胞和红细胞）能够浸润到脱细胞组织中。一般来说，细胞浸润到脱细胞组织的深度随交联程度的增加而降低。炎性细胞的浸润伴随着脱细胞组织的降解。由于早期降解，在新鲜（未交联）和30%交联度的脱细胞组织中未观察到组织再生。这是因为这两个样品提供的支架在浸润细胞开始分泌自身细胞外基质之前就已经完全降解了。相比之下，通过组织学检查、免疫组织化学染色、透射电子显微镜和变性温度测量，在60%和95%交联度的脱细胞组织中观察到了组织再生（成纤维细胞、新胶原纤维和新毛细血管）。95%交联度的脱细胞组织比60%交联度的脱细胞组织对酶解的抵抗力更强。因此，在整个研究过程（术后1年）中，95%交联度的脱细胞组织外层的组织再生受到限制，而60%交联度的脱细胞组织在整个样品中都观察到了组织再生。总之，交联程度决定了脱细胞组织的降解速率及其组织再生模式。
