Department of Anatomy and Human Biology, The University of Western Australia, Nedlands, Perth, WA 6009, Australia.
Restor Neurol Neurosci. 1994 Jan 1;6(3):221-37. doi: 10.3233/RNN-1994-6306.
The efficacy of Schwann cell-filled polycarbonate tubes as a bridging substrate for regrowing axons following lesions of the rat optic tract or cerebral cortex has been assessed after short (11-31 days) or long (82-119 days) survival times. Tubes were impregnated with Iaminin and poly-L-lysine, soaked in basic FGF and filled with Schwann cells. They were implanted into optic tract lesions in 34 rats aged 15-21 days and into cortical lesion cavities in 3 adult rats. Gelfoam soaked in basic FGF and Schwann cell conditioned medium was placed over the tubes. In one group of rats, axon regrowth into implants was assessed using neurofilament antibody RT97; antibodies to proteolipid protein, Po, Iaminin, the low-affinity nerve growth factor receptor (NGFr), S-100 and EDI were also used to study myelination and the cellular content of the tubes. In a second group of rats, anterograde tracing techniques were used to specifically identify host retinal axons within the implanted polymers. After long survival times, the relationships between regrown axons and cells inside the tubes were also examined ultrastructurally. In all implants examined immunohistochemically at short survival times, large numbers of RT97+ axons were found throughout the tubes, usually in association with Iaminin+, NGFr+ Schwann cells. At longer survival times, viable Schwann cells were still present, but tubes contained fewer axons and less cellular material. This material often formed a cord (200-250 μm thick) which extended the length of the implant. In the second group of rats, labelled retinal axons were found in 11 of the 16 implants that were attached to the dLGN. Axons regrew up to 1 mm but did not reach the distal (tectal) end of the implants. Interestingly, there was no evidence of myelinogenesis by either implanted Schwann cells or by host-derived oligodendroglia which had migrated into the tubes. Oligodendroglia were usually encircled by processes, many of which originated from Schwann cells, suggesting that the grafted cells may have been involved in isolating the central glia. The data show that Schwann cell-filled polycarbonate tubes provided a favourable milieu for axonal regeneration in the short term; however over time there was a decrease in the cellular and fibre content of the tubes. After intracranial implantation, an additional supporting matrix inside the polycarbonate tubes may aid in providing an environment conducive to the long term maintenance of regenerated retinal and other axons.
施万细胞填充聚碳酸酯管作为桥接物在大鼠视神经或大脑皮质损伤后的轴突再生中的功效，在短期（11-31 天）或长期（82-119 天）存活后进行了评估。管内浸渍层粘连蛋白和多聚-L-赖氨酸，浸泡在碱性成纤维细胞生长因子中并填充施万细胞。它们被植入 34 只 15-21 天大的大鼠的视神经损伤和 3 只成年大鼠的皮质损伤腔中。用碱性成纤维细胞生长因子和施万细胞条件培养基浸泡的明胶海绵置于管上方。在一组大鼠中，使用神经丝抗体 RT97 评估轴突向植入物的再生；还使用针对蛋白脂质蛋白、Po、层粘连蛋白、低亲和力神经生长因子受体（NGFr）、S-100 和 EDI 的抗体来研究髓鞘形成和管内细胞含量。在第二组大鼠中，使用顺行追踪技术专门鉴定植入聚合物内的宿主视网膜轴突。在长期存活后，还通过超微结构检查研究了再生轴突与管内细胞之间的关系。在所有在短期存活时进行免疫组织化学检查的植入物中，在管内发现了大量 RT97+轴突，通常与层粘连蛋白+、NGFr+施万细胞相关。在较长的存活时间，仍存在存活的施万细胞，但管内轴突和细胞物质较少。该物质通常形成一条索（200-250μm 厚），延伸至植入物的长度。在第二组大鼠中，在 16 个与 dLGN 相连的植入物中有 11 个中发现了标记的视网膜轴突。轴突再生长达 1 毫米，但未到达植入物的远端（顶盖）端。有趣的是，无论是植入的施万细胞还是迁移到管内的宿主来源的少突胶质细胞，都没有证据表明发生了髓鞘形成。少突胶质细胞通常被突起环绕，其中许多突起起源于施万细胞，这表明移植的细胞可能参与了中枢神经胶质的隔离。数据表明，施万细胞填充的聚碳酸酯管在短期内为轴突再生提供了有利的环境；然而，随着时间的推移，管内的细胞和纤维含量减少。在颅内植入后，聚碳酸酯管内的额外支撑基质可能有助于提供有利于长期维持再生视网膜和其他轴突的环境。
