异种羊脱细胞真皮基质与白体微粒皮复合移植后创面愈合及COX-2、VEGF的表达研究

目的制备异种羊脱细胞真皮基质（ADM），观察异种羊ADM与白体微粒皮复合移植的组织学变化，以及免疫组化法检测环氧化酶-2（COX-2）、血管内皮生长因子（VEGF）在复合移植过程中的表达。方法用0．25％胰蛋白酶和O．5％曲拉通（TritonX-100）溶液联合脱细胞法制备异种羊ADM。以48只Wistar大鼠为动物模型随机分为2组，每组各24只，背部做4cm×3cm全层皮肤缺损，分组采用羊ADM＋自体微粒皮＋异体皮（实验组）及自体微粒皮＋异体皮（对照组）覆盖，术后2、4、6周观察植皮区愈合情况，检测创面收缩率；同时，在以上不同时间段处死大鼠做组织病理学观察及免疫组化检查。结果（1）通过实验可成功制备出合格的异种羊ADM，脱细胞异种皮的镜下观察可见基质中的表皮已经完全除去，胶原纤维粗细均匀，排列规则，没有细胞成份存在。（2）进行移植术后，观察6周，两组皮片创面基本愈合，两组创面收缩率差异具有统计学意义（P〈0．05），实验组术区收缩程度低，组织学检查可见成纤维细胞和血管长入，胶原纤维、弹力纤维结构排列规则；对照组创面收缩明显，组织学检查见成纤维细胞和血管无规则生长，胶原纤维、弹力纤维结构排列紊乱。两组大鼠创面COX-2、VEGF表达差异无统计学意义（P〉0．05）。结论异种羊ADM在彻底脱除了基质中有免疫原性的细胞成分的同时，义保留了组织的基本结构，成为极低抗原性的真皮支架，是一种良好的真皮替代物；异种羊ADM与自体微粒皮复合移植后外观和功能优于白体微粒皮移植；COX-2，VEGF可能参与了创面的修复。

Wound healing and expression of cox-2, VEGF after transplantation of sheepskin acellular dermal matrix combined with micro-autograft of skin

Objective To investigate an appropriate method for the preparation of sheepskin acellular dermal matrix（ADM）, we observed the expression of cycloxygenase- 2（COX-2）, vascular endothelial growth factor（VEGF） by using immunohistochemistry method, and the changes of histological structure on the cograft of auto-microskin and sheepskin ADM. Methods Using 0.25% trypsin and 0.5%TritonX-100 to prepare sheepskin ADM.The fullthickness skin defects were made to 4 cm× 3 cm in the back of Wistar rats. The 48 wounds were assigned to test and control groups.The wounds in test group were grafted with auto-microskin and sheepskin ADM, while the wounds in control group were grafted with auto-microskin. All wounds were coverd with the allo- split-thickness skin. The samples of grafted skin of 2, 4, and 6 weeks after operation were prepared with immunohistochemical examination and observed histological structure with light microscope. Simultaneously the wound healing condition and contraction rate of the two groups were detected. Results （1）Under light microscopy, the epidermis was found completely removed, Collagen fibers well-distributed and there was not any cellular component in dermis.（2） After transplantation, the two groups wounds were generally healed during 6 weeks observation. The contraction rate exhibited obvious difference（P〈0.05）. Compared with the control group, the wounds of the test group had lower contraction rate. Simultaneously, histological examination revealed that normal vascular structure was identified in the grafted skin. The structure of collagen fibres appeared integrated clear with regular arrangement. There were no significant differences of the expression of COX-2 and VEGF（P 〉 0.05）between the two groups. Conclusions Sheepskin ADM has not only removed immunogenicity cellular composition thoroughly, but also preserved tissue of basic structure and complete collagen scaffold. It becomes very low antigenic demis scaffold, and it is a good dermal substitute. Compared with t