PharmaBiotec, Department of Anatomy and Cell Biology, University of Odense, Odense, Denmark Department of Cellular Biology, Faculty of Biology, Universidad Complutense de Madrid, Madrid, Spain.
Restor Neurol Neurosci. 1996 Jan 1;10(1):13-24. doi: 10.3233/RNN-1996-10103.
Exchange of nerve connections between developing neural grafts and adult recipient brains is enhanced for grafts placed in excitotoxic lesions, which spare recipient brain afferent axons in otherwise neuron-depleted lesion areas. In previous studies of hippocampal grafts placed in such lesions, we have used anterograde axonal degeneration, histochemical Timm staining and acetylcholinesterase to demonstrate host-graft interconnectivity. In this study, we have now used three anterograde axonal tracers, Phaseoulus vulgaris-leukoaglutinin (PHA-L), biocytin and biotinylated dextran amine (BDA), which allow individual fibers to be traced. Adult male rats with 1-week-old axon-sparing ibotenic acid lesions of the dorsal CA3 region or fascia dentata were grafted into the respective lesions with suspensions of fetal (El8-19) CA3 cells or a block of neonatal fascia dentata tissue. One to twelve months later, recipients were injected with Phaseoulus vulgaris-leukoaglutinin or biocytin in the hippocampus contralateral to the graft to trace the possible ingrowth and distribution within the transplants of host commissural axons, or into the transplants with biotinylated dextran amine in order to trace outgrowing graft fibers. In rats with succesfull host Phaseoulus vulgaris-leukoaglutinin or biocytin injections, the CA3 and fascia dentata transplants were innervated by labelled host commissural fibers. In the dentate transplants, most commissural fibers projected as normally to the inner part of the molecular layer, with fewer aberrant fibers extending more superficially into the molecular layer. Following injections into the fascia dentata and CA3 grafts of biotinylated dextran amine, labelled graft fibers were traced into the ipsilateral host dentate hilus, CA3 and CA1. From some CA3 containing grafts, a few labelled fibers were also observed passing through the host fimbria-fornix to the lateral septum on the grafted side. A few fibers were projected as far as to the most septal levels of the contralateral CA1.
发育中的神经移植物与成年受者大脑之间的神经连接交换在置于兴奋性损伤中的移植物中增强，所述兴奋性损伤在其他情况下使神经元耗竭的损伤区域中的受者脑传入轴突免受损伤。在先前置于此类损伤中的海马移植物的研究中，我们使用顺行轴突变性、组织化学 Timm 染色和乙酰胆碱酯酶来证明宿主-移植物的连接性。在这项研究中，我们现在使用了三种顺行轴突示踪剂，即菜豆植物凝集素（PHA-L）、生物胞素和生物素化葡聚糖胺（BDA），它们可以追踪单个纤维。具有 1 周龄的背侧 CA3 区或齿状回轴突保存性异柠檬酸损伤的成年雄性大鼠用胚胎（El8-19）CA3 细胞悬浮液或新生齿状回组织块移植到相应的损伤中。1 至 12 个月后，将生物胞素或 BDA 注射到移植物对侧的海马中，以追踪宿主连合轴突可能向内生长并分布于移植物内，或注入移植物中，以追踪移植的纤维向外生长。在成功进行宿主 PHA-L 或生物胞素注射的大鼠中，CA3 和齿状回移植物被标记的宿主连合纤维支配。在齿状回移植物中，大多数连合纤维正常投射到分子层的内部，较少的异常纤维延伸到分子层的更浅层。在将生物素化葡聚糖胺注入齿状回和 CA3 移植物后，追踪到标记的移植物纤维进入同侧宿主齿状回回、CA3 和 CA1。从一些包含 CA3 的移植物中，也观察到一些标记的纤维穿过宿主穹窿伞-穹窿到移植侧的外侧隔室。一些纤维投射到对侧 CA1 的最隔室水平。
