Tønder N, Sørensen T, Zimmer J
PharmaBiotec, Institute of Neurobiology, University of Aarhus, Denmark.
Prog Brain Res. 1990;83:391-409. doi: 10.1016/s0079-6123(08)61264-9.
Hippocampal CA3 neurons from fetal rats were grafted to excitotoxic lesions in the CA3 subfield of the adult rat hippocampus and the formation of graft-host brain nerve connections examined. The excitotoxic lesions were induced by localized, stereotaxic injection of ibotenic acid (IA), a glutamic acid agonist, into CA3 of the dorsal hippocampus. The result was a so-called axon-sparing lesion with localized degeneration of nerve cells, but preservation of the extrinsic afferent fibers, now deprived of their targets. One week after the lesion a suspension of embryonic (E18-20) CA3 cells was grafted to the lesion site. Six weeks or more later the recipient brains were processed and analyzed by ordinary cell stains, histochemistry for acetylcholinesterase (AChE) and heavy metals (Timm staining), immunohistochemistry for the neuropeptides cholecystokinin and somatostatin and glial fibrillary acidic protein (GFAP) for astroglia, electron microscopy, and axonal tracing with retrogradely axonal transported fluorescent dyes or lesion-induced, anterograde degeneration combined with silver staining or electron microscopy. More than 90% of the grafts survived. They contained the normal types of CA3 neurons, which are mainly pyramidal cells, in addition to some normal, peptidergic, cholecystokinin- and somatostatin-reactive neurons. The grafts were innervated by AChE-positive, host cholinergic fibers, Timm-positive mossy fiber terminals from the host fascia dentata, and host commissural fibers traced by axonal degeneration. Efferent transplant projections were traced to the ipsilateral host CA1 (Schaffer collaterals) and the contralateral host hippocampus by retrograde axonal transport of fluorochromes injected into these host brain areas. All grafts analyzed by electron microscopy contained axonal varicosities resembling axonal growth cones even after long survival times. The results demonstrate that fetal rat hippocampal neurons, grafted to excitotoxic, axon-sparing lesions in the adult brain, can become both structurally and connectively well incorporated in the mature host central nervous system.
将胎鼠海马CA3区神经元移植到成年大鼠海马CA3亚区的兴奋性毒性损伤部位，并检测移植体与宿主脑之间神经连接的形成情况。兴奋性毒性损伤是通过将谷氨酸激动剂碘代乙酰脲酸（IA）局部立体定向注射到背侧海马CA3区诱导产生的。结果形成了所谓的轴突保留性损伤，即神经细胞局部变性，但外在传入纤维得以保留，这些纤维现在失去了它们的靶标。损伤一周后，将胚胎（E18 - 20）CA3细胞悬液移植到损伤部位。六周或更长时间后，对受体脑进行处理，并通过普通细胞染色、乙酰胆碱酯酶（AChE）组织化学和重金属（Timm染色）、神经肽胆囊收缩素和生长抑素以及星形胶质细胞的胶质纤维酸性蛋白（GFAP）免疫组织化学、电子显微镜以及用逆行轴突运输荧光染料或损伤诱导的顺行变性结合银染色或电子显微镜进行轴突追踪分析。超过90%的移植物存活下来。它们包含正常类型的CA3神经元，主要是锥体细胞，此外还有一些正常的、肽能的、对胆囊收缩素和生长抑素反应的神经元。移植物接受了来自宿主的AChE阳性胆碱能纤维、来自宿主齿状回的Timm阳性苔藓纤维终末以及通过轴突变性追踪到的宿主连合纤维的支配。通过向这些宿主脑区注射荧光染料进行逆行轴突运输，追踪到传出移植投射到同侧宿主CA1区（Schaffer侧支）和对侧宿主海马。即使在长时间存活后，通过电子显微镜分析的所有移植物都含有类似于轴突生长锥的轴突膨体。结果表明，移植到成年脑兴奋性毒性、轴突保留性损伤部位的胎鼠海马神经元在结构和连接上都能很好地整合到成熟的宿主中枢神经系统中。
