Department of Anatomy and Human Biology, The University of Western Australia, Nedlands, WA 6009 (Australia).
Restor Neurol Neurosci. 1991 Jan 1;2(4):233-48. doi: 10.3233/RNN-1991-245611.
Attempts were made to enhance the regrowth of retinal axons which had been lesioned in the brachial region of the rat optic tract. Pieces of nitrocellulose paper (Millipore) were placed into the lesioned area between the dorsal lateral geniculate nucleus (dLGN) and superior colliculus (SC) in 13- to 18-day-old Wistar rats. Five types of implant were used: (1) uncoated implants, (2) coated with Poly-l-lysine (PLL), (3) coated on one side with cortical astrocytes, (4) coated with tectal astrocytes and (5) coated with Schwann cells. About half the Schwann cell-covered implants were precoated with PLL. Schwann cell-coated implants (16-40 × 103 cells per implant) were placed with the cells lying on either the dorsal or ventral (inverted) surface of the paper. 5-7 weeks after surgery, eyes were injected with WGA-HRP, the animals were perfused and frozen or vibratome sections (40-50 μm) processed for TMB histochemistry. Selected sections containing retinal axons were osmicated and prepared for electron microscopic examination. 45 out of 86 implants were found attached to the caudal dLGN. A small number of retinal axons were found growing onto the rostral end of one uncoated implant, two PLL-coated implants and over the surface of 4 of the astrocyte-coated implants. The densest and most extensive growth was seen on the Schwann cell-coated implants. In 15 of the 30 animals with such implants attached to the dLGN, retinal axons were found regrowing for 50-1120 μm (mean 530 μum). In about half of these rats (8 out of 15), the regrowth involved relatively large numbers of optic axons which were sometimes densely packed together. In the subgroup of Schwann cell-coated implants where the cells were placed upwards, retinal axons regrew on the dorsal surface of the paper for more than 500 μm in 7 animals. Almost no growth was seen on the uncoated (ventral) surface of the implants. In the subgroup of inverted implants, where the Schwann cells were placed downwards, in 4 animals retinal axon regrowth was densest on the ventral surface and extended for 300-550 μm. In 3 cases, occasional axons were also seen on the dorsal implant surface. Myelin sheaths surrounding some of the regenerating axons had PNS characteristics, suggesting that they were formed by the implanted Schwann cells, but most of the myelin appeared to be of central origin. The data suggest that Schwann cells placed just caudal to the dLGN and adjacent to lesioned retinal axons can enhance and direct the regrowth of these axons in the rat optic tract.
试图促进大鼠视束臂部损伤的视网膜轴突再生。在 13-18 天大的 Wistar 大鼠的背外侧膝状体核（dLGN）和上丘（SC）之间的损伤部位放置硝化纤维素纸（Millipore）片。使用了 5 种类型的植入物：（1）未涂层植入物，（2）用聚-L-赖氨酸（PLL）涂层，（3）一侧用皮质星形胶质细胞涂层，（4）用顶盖星形胶质细胞涂层，（5）用施万细胞涂层。大约一半的施万细胞覆盖的植入物预先用 PLL 涂层。将施万细胞涂层植入物（每个植入物 16-40×103 个细胞）放置，使细胞位于纸张的背侧或腹侧（倒置）表面上。手术后 5-7 周，用 WGA-HRP 注射眼睛，对动物进行灌注和冷冻或振动切片（40-50μm）处理，进行 TMB 组织化学染色。选择含有视网膜轴突的切片进行锇固定，并准备进行电子显微镜检查。在 86 个植入物中有 45 个附着在尾侧 dLGN 上。在一个未涂层植入物、两个 PLL 涂层植入物和 4 个星形胶质细胞涂层植入物的近侧端发现少量视网膜轴突生长。在施万细胞涂层植入物上观察到最密集和最广泛的生长。在附着于 dLGN 的 30 只动物中有 15 只发现视网膜轴突再生了 50-1120μm（平均 530μm）。在这些大鼠中，有 8 只（15 只中的 8 只）涉及相对大量的视神经轴突再生，这些轴突有时紧密堆积在一起。在施万细胞涂层植入物的亚组中，其中细胞向上放置，在 7 只动物中，视网膜轴突在纸张的背侧表面上再生超过 500μm。在植入物的未涂层（腹侧）表面几乎看不到生长。在倒置植入物的亚组中，施万细胞向下放置，在 4 只动物中，视网膜轴突再生最密集在腹侧表面，延伸 300-550μm。在 3 例中，偶尔也可以在背侧植入物表面看到一些轴突。一些再生轴突周围的髓鞘具有 PNS 特征，表明它们是由植入的施万细胞形成的，但大多数髓鞘似乎来自中枢神经系统。数据表明，放置在 dLGN 尾侧并紧邻损伤的视网膜轴突附近的施万细胞可以增强和引导大鼠视束中这些轴突的再生。
