载NGF海藻酸凝胶-聚乳酸复合导管修复兔面神经缺损实验研究

目的    观察载神经生长因子（nerve growth factors, NGF）海藻酸凝胶-聚乳酸复合导管修复面神经缺损的作用。  方法    建立白兔面神经缺损模型，将面神经断端植入制备好的载NGF海藻酸凝胶-聚乳酸复合导管内2 mm，使面神经两断端之间距离为10 mm，将导管两端与神经固定缝合皮肤。再随机将12只大白兔分为术后4、8、12周组。实验结束后切开大白兔面神经吻合部位，选取神经导管近、中和远端组织进行HE染色，观察神经生长及导管降解情况。  结果    实验白兔手术伤口Ⅰ期愈合，无局部坏死、移植物排出及全身不良反应。术后4周导管壁有巨噬细胞浸润，导管近端雪旺细胞、成纤维细胞增生，新生小血管丰富；8周可见导管壁变薄，有成纤维细胞附着，巨噬细胞浸润，导管内有神经束样结构，束间纤维分隔，外层纤维包膜增厚，新生小血管减少；12周可见神经导管壁进一步分解，胶原纤维增生，导管内神经纤维结构接近正常，轴突样结构增粗，外层纤维包膜变薄。  结论    载NGF海藻酸凝胶-聚乳酸复合导管能较好的引导面神经再生，具有良好的组织相容性。

The study of the composite conduit containing nerve growth factor and alginate gel-polylactic acid for repair of facial nerve injury in rabbit

Objective　To observe the effect of the composite conduit containing the nerve growth factor (NGF) and alginate gel-polylactic acid for repair of facial nerve injury in the rabbit.    Methods   Firstly, rabbit facial nerve injury model was established. The facial nerve stump was implanted into the prepared composite conduit containing NGF and alginate gel-polylactic acid for 2 mm, to keep the two facial nerve stumps for 10 mm. Then, the two ends of the catheter with nerve and were fixedand the skin sutured.  The 12 rabbits were randomly divided into 3 groups: 4, 8 or 12 weeks after operation. After the experiment, the anastomotic site of facial nerve was cut and near, middle and distal tissue of the nerve conduit were selected for HE staining.  Results  The experimental rabbits showedprimary surgical wound healing, with no local necrosis, graft discharge or systemic adverse reactions observed. There was macrophage infiltration in catheter wall 4 weeks after operation; meanwhile, there were rich Schwann cells, fibroblasts and new small blood vessels in catheter proximal in this group. For 8 weeks after operation, fibroblasts and macrophages attaching to the catheter wallwas thinner than 4 weeks. Moreover, there was nerve bundle-like structure and separated fiber bundles within the conduit. The outer fibrous capsule was thickened and the small blood vessels reduced. For 12 weeks after operation, the nerve conduit wall was further decomposed associated with collagen fibers hyperplasia. The intraductal nerve fiber was close to normal, which showed thickening axon-like structure and thinning outer fibrous capsule. Conclusion   The composite conduit containing NGF and alginate gel-polylactic acid shows good histo-compatibility and can effectively induce the facial nerve regeneration.