组织工程支架在犬急性脊髓损伤修复中应用的初步研究

目的探讨携带神经干细胞的聚碳酸亚丙酯poly（propylene carbonate），PPC]可降解支架移植在犬脊髓急性损伤后修复中的作用。方法制作犬T13脊髓左侧半切损伤模型。将实验动物随机分为3组：细胞支架组在损伤后1周时将填充神经干细胞的PPC可降解支架植入损伤区．支架组只植入支架，对照组不作移植。8周后观察支架的组织反应、降解情况及神经干细胞的迁移分化和脊髓轴突再生情况。结果支架部分降解，管腔内未见瘢痕侵入。神经干细胞向支架邻近部位广泛迁移、扩散，并分化为3种神经细胞表型。神经丝蛋白（NF）及髓鞘碱性磷酯蛋白（MBP）免疫组化显示细胞支架组脊髓损伤区邻近部位的继发损害较其他组轻。结论携带神经干细胞的PPC可降解支架在犬脊髓组织中无明显组织反应．能够抵御瘢痕侵入：其携带的神经干细胞能够整合入邻近脊髓组织并起到一定保护作用。

Preliminary study of application of tissue engineering scaffolds in the repair of acutely injured canine spinal cord

Objective To probe the role of transplantation of poly(propylene carbonate) (PPC) degradable scaffold seeded with neural stem cells in repair of acutely injured canine spinal cord. Methods Left side hemisection of the spinal cord was carried out at T13 in adult dogs. The animals were assigned to 3 groups: control group, scaffold-transplanted group, and scaffold-neural stem cell-treated group. At the 8th week after the treatment, the tissue response to the scaffold, degradation of the scaffold, glial scar, migration and differentiation of the neural stem cells, and regeneration and remyelination of the axons in the injured region were observed. Results Degradation of the scaffold was found, with no glial scar existing in lumina of the scaffold. Transplanted neural stem cells migrated extensively to the surrounding regions of the spinal cord. Transplanted cells differentiated into three neural cell phenotypes. Immunohistochemical staining of neurofilament and myelin basic protein exhibited the vicinity of the injury region showed more intact myelinated fibers and a less myelin degradation in the vicinity of the injury region in the scaffold-neural stem cell-treated group. Conclusions PPC degradable scaffold can inhibit the ingrowth of glial scar, with little immune response. The transplanted neural stem cells can integrate themselves into the surrounding tissue of injured region in the canine spinal cord and provide protection against secondary injury.