The search for a suitable material to promote regeneration after long-distance peripheral nerve defects turned the spotlight on spider silk. Nerve conduits enriched with native spider silk fibers as internal guiding structures previously demonstrated a regenerative outcome similar to autologous nerve grafts in animal studies. Nevertheless, spider silk is a natural material with associated limitations for clinical use. A promising alternative is the production of recombinant silk fibers that should mimic the outstanding properties of their native counterpart. However, in vitro data on the regenerative features that native silk fibers provide for cells involved in nerve regeneration are scarce. Thus, there is a lack of reference parameters to evaluate whether recombinant silk fiber candidates will be eligible for nerve repair in vivo. To gain insight into the regenerative effect of native spider silk, our study aims to define the behavioral response of primary Schwann cells (SCs), nerve-associated fibroblasts (FBs), and dorsal root ganglion (DRG) neurons cultured on native dragline silk from the genus Nephila and on laminin coated dishes. The established multi-color immunostaining panels together with confocal microscopy and live cell imaging enabled the analysis of cell identity, morphology, proliferation, and migration on both substrates in detail. Our findings demonstrated that native spider silk rivals laminin coating as it allowed attachment and proliferation and supported the characteristic behavior of all tested cell types. Axonal out-growth of DRG neurons occurred along longitudinally aligned SCs that formed sustained bundled structures resembling Bungner bands present in regenerating nerves. The migration of SCs along the silk fibers achieved the reported distance of regenerating axons of about 1 mm per day, but lacked directionality. Furthermore, rFBs significantly reduced the velocity of rSCs in co-cultures on silk fibers. In summary, this study (a) reveals features recombinant silk must possess and what modifications or combinations could be useful for enhanced nerve repair and (b) provides assays to evaluate the regenerative performance of silk fibers in vitro before being applied as internal guiding structure in nerve conduits in vivo.

中文翻译：

---

定义天然蜘蛛丝纤维对原代雪旺细胞、感觉神经元和神经相关成纤维细胞的再生作用


寻找合适的材料来促进远距离周围神经缺陷后的再生，使蜘蛛丝成为人们关注的焦点。富含天然蜘蛛丝纤维作为内部引导结构的神经导管先前在动物研究中表现出与自体神经移植相似的再生结果。然而，蜘蛛丝是一种天然材料，其临床应用存在一定的局限性。一种有前途的替代方案是生产重组丝纤维，该纤维应模仿其天然对应物的出色特性。然而，有关天然丝纤维为参与神经再生的细胞提供的再生特征的体外数据很少。因此，缺乏参考参数来评估重组丝纤维候选物是否适合体内神经修复。为了深入了解天然蜘蛛丝的再生作用，我们的研究旨在定义在天然蜘蛛丝上培养的原代雪旺细胞（SC）、神经相关成纤维细胞（FB）和背根神经节（DRG）神经元的行为反应Nephila 属和层粘连蛋白涂层培养皿上。建立的多色免疫染色面板与共焦显微镜和活细胞成像相结合，可以详细分析两种基质上的细胞身份、形态、增殖和迁移。我们的研究结果表明，天然蜘蛛丝可与层粘连蛋白涂层相媲美，因为它允许附着和增殖，并支持所有测试细胞类型的特征行为。 DRG 神经元的轴突生长沿着纵向排列的 SC，形成持续的束状结构，类似于再生神经中存在的 Bungner 带。 SC 沿着丝纤维的迁移实现了每天约 1 毫米的再生轴突距离，但缺乏方向性。此外，rFB 显着降低了丝纤维共培养中 rSC 的速度。总之，这项研究（a）揭示了重组丝必须具备的特征以及哪些修饰或组合可用于增强神经修复；（b）提供了在用作神经修复中的内部引导结构之前评估丝纤维的体外再生性能的测定方法。体内的神经导管。