骨髓间充质干细胞分化为血管内皮细胞的实验研究

目的：探讨骨髓间充质干细胞（MSCs)分化为肉芽组织中血管内皮细胞的可能性。及其参与创面修复的可能机制。方法：抽取小型香猪的骨髓，经密度梯度离心分离、纯化MSCs，体外培养扩增后，应用溴脱氧尿嘧啶（BrdU)标记技术标记细胞。于已抽取骨髓的小型香猪背部制作全层皮肤缺损创面，即刻以纤维蛋白胶为载体，将已标记的MSC回植到供体动物创面上。术后2、4、6、8、12周切取创面组织，行BrdU和因子Ⅷ（FⅧ）免疫组织化学染色，进行对比观察。结果：BrdU阳性的MSCs多聚集在创面肉芽组织中的小血管周围，且有个别血管内皮细胞也呈现BrdU 阳性。部分BrdU阳性的MSCs胞浆中亦有FⅧ表达。结论：创面愈合过程中，MSCs与肉芽组织中小血管的形成密切相关。在创面微环境下，MSCs可分化为血管内皮细胞，并参与创面修复。

An experimental study on the differentiation of bone marrow mesenchymal stem cells into vascular endothelial cells

OBJECTIVE: To investigate the feasibility of differentiation of bone marrow mesenchymal stem cells (MSCs) into vascular endothelial cells and the mechanism of its involvement in wound healing. METHODS: Porcine MSCs were harvested from porcine marrow, and they were isolated and purified by density gradient centrifugation. After being cultured and amplified in vitro, the MSCs were labelled with BrdU (5-bromodeoxy-uridine). Full skin loss wound was created on the back of the mini-swine whose bone marrow was obtained. The labelled MSCs with fibrin glue as the vector were regrafted back to the donor animal wound. The wound tissue specimens were harvested at 2, 4, 6, 8 and 12 post-operation weeks and were immunohistochemically stained by BrdU and factor VIII (FVIII) for comparative study. RESULTS: Most BrdU positive cells aggregated around small blood vessels in the granulation tissue of the wounds. Only individual vascular endothelial cells were BrdU positive. There was FVIII expression in the cytoplasm of BrdU positive cells. CONCLUSION: MSCs were closely correlated with the formation of small blood vessels in granulation tissue during wound healing process. The porcine MSCs possessed the potential to differentiate into vascular entoehelial cells and to participate in wound healing under the micro-enviroment of the wound.