血管束法构建血管化组织工程骨支架材料的组织学观察

Histological Study of Vascularized Tissue-engineered Scaffolds by Two Arteriovenous Bundles

目的:比较末端结扎和不结扎两种血管束法在珊瑚中预构血管化的程度,探索一种先血管后成骨,最终解决骨组织工程血管化的方法。方法:选择新西兰兔的股动脉和股静脉解剖分离形成血管束,方法一是末端切断结扎形成动静脉环,环绕套入珊瑚支架的侧槽中;方法二是血管束保持血流通畅,动静脉分别套入珊瑚支架的两侧槽中。外用ePTFE膜包裹隔绝,植入大腿皮下。单纯珊瑚块埋植于皮下作为空白对照。术后2、4、6周行大体形态学和组织学检查,分析珊瑚孔隙中组织结构和血管新生情况并作定量分析。结果:珊瑚侧槽、表层和深层间隙内有大量血管和纤维结缔组织新生,4周基本充满全层,6周血管化明显。组织学和定量分析显示血管通畅组较末端结扎组和空白对照组血管生成更明显,空白组主要是纤维组织增生。结论:珊瑚植入血管束并被隔绝后可以形成血管化的活体组织,血管化的珊瑚有望作为骨组织工程的支架材料,为下一步构建组织工程骨提供早期营养。

Objective： To investigate the effect of prefabricated vascularized natural corals in bone tissue engineering through angiogenesis prior to bone formation. Methods： 21 three months old male New Zealand rabbits weighed approximately 2000-2500 g each were randomly divided into 3 groups. In group A （n=9）, a flow-through vessels between the femoral artery and vein were placed in the tateral groove of coral. In group B （n=9）, a ligated pedicle arteriovenous bundle at the end of femoral artery and vein was placed around the coral in the same manner. The implants were wrapped by an ePTFE membrane. In group C （n=3）, the coral was embedded under the skin, no vessels were inserted. Evaluation methods included gross morphological observations, histological examination, and quantitative statistics of blood vessel density. Results： After 2, 4 and 6 weeks, new fibrovascular tissues developed around the surface and deep interspaces of corals, most of the vessels distributed around the arteries and veins. At 4 weeks, the coral has been completely encapsulated by new granulation tissue. Histological examination showed new fibrovascular tissue proliferation was evident in group A, sparse in group B, and less in group C. The blood vessel density was higher in group A than those in group B and group C. Conclusion： A vascularized coral might be expected to be used in bone tissue engineering.