Fetal spinal cord tissue in mini-guidance channels promotes longitudinal axonal growth after grafting into hemisected adult rat spinal cords.
Fetal spinal cord tissue in mini-guidance channels promotes longitudinal axonal growth after grafting into hemisected adult rat spinal cords.
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DOI：
10.1155/np.1999.103
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发表时间：
1999
影响因子：
3.1
通讯作者：
Xu XM
中科院分区：
文献类型：
--
作者：
Bamber NI;Li H;Aebischer P;Xu XM
将固体胎儿脊髓 (FSC) 组织接种到半透性微型引导通道中，测试其促进成年大鼠胸廓中部 (T8) 半切所产生的间隙中轴突生长的能力。胚胎第 13 至 15 天时，收获胎儿胸脊髓并轻轻吸入微型引导通道（直径 1.25 毫米，长度 3.0 毫米）。小心保持 FSC 的头尾方向。在对照大鼠中，FSC通道移植物结构在植入半切的脊髓之前经历5次冷冻/解冻循环以产生非存活的移植物。所有病例均显示不同直径的完整组织索跨越病变腔的头尾范围，并且宿主-移植物组织在两个界面处整合。免疫荧光结果表明，FSC 组织缆内存在大量神经丝阳性轴突。用降钙素基因相关肽对这些轴突的亚群进行双重标记表明了它们的周围神经系统（PNS）起源。在吻侧宿主-移植物界面附近发现了下降的血清素能和去甲肾上腺素能轴突，但没有观察到它们生长到 FSC-移植物中。用菜豆-白细胞凝集素对本体脊髓轴突进行顺行追踪，证明轴突已再生到 FSC 移植物中，并纵向行进至通道的远端。观察到很少有轴突穿过远端宿主-移植物界面进入宿主脊髓。用甲苯胺蓝染色的组织索中点的横截面分析表明，与冻融对照移植物（155±50；n=5）相比，存活的 FSC 移植物（1455±663，平均值±S.E.M.；n=6）中的有髓轴突显着增加（P<0.01）。除了有髓鞘轴突外，在电子显微镜水平下在组织电缆中还观察到许多无髓鞘轴突。还观察到具有典型雪旺细胞的类似于三七总皂甙的区域，以及具有神经元和中枢神经纤维的类似于中枢神经系统的区域。在冻融对照移植物中，既没有观察到存活的神经元，也没有观察到中枢神经纤维。使用固蓝和二脒黄的逆行追踪表明，FSC 移植物内的神经元将轴突从头侧和尾侧宿主-移植物界面延伸到宿主脊髓中至少 2 毫米。我们的结论是，半透性引导通道内的可行 FSC 移植物既可以作为纵向轴突生长的许可桥梁，也可以作为在成年大鼠脊髓损伤部位传递信息的潜在中继。
Solid fetal spinal cord (FSC) tissue, seeded into semipermeable mini-guidance channels, was tested for the ability to promote axonal growth across the gap created by a midthoracic (T8) hemisection in adult rats. Fetal thoracic spinal cords, at embryonic days 13 to 15, were harvested and gently aspirated into mini-guidance channels (1.25 mm in diameter and 3.0 mm in length). Care was taken to maintain the rostro-caudal orientation of the FSC. In control rats, the FSC-channel congraft struct was exposed to 5 freeze/thaw cycles to produce non-viable grafts before implantation into the hemisected cord. All cases revealed intact tissue cables of various diameters spanning the rostro-caudal extent of the lesion cavity, with integration of host-graft tissues at both interfaces. Immunofluorescence results indicated that numerous neurofilament-positive axons were present within the FSC tissue cable. Double-labeling of a subpopulation of these axons with calcitonin generelated peptide indicated their peripheral nervous system (PNS) origin. Descending serotonergic and noradrenergic axons were found in the proximity of the rostral host-graft interface, but were not observed to grow into the FSC-graft. Anterograde tracing of propriospinal axons with Phaseolus vulgaris-leucoagglutinin demonstrated that axons had regenerated into the FSC-graft and had traveled longitudinally to the distal end of the channel. Few axons were observed to cross the distal host-graft interface to enter the host spinal cord. Cross-sectional analysis at the midpoint of the tissue cable stained with toluidine blue demonstrated a significant increase (P<0.01) in myelinated axons in viable FSC grafts (1455±663, mean±S.E.M.; n=6) versus freeze-thaw control grafts (155±50; n=5). In addition to the myelinated axons, many unmyelinated axons were observed in the tissue cable at the electron microscopic level. Areas resembling the PNS with typical Schwann cells, as well as those resembling the central nervous system with neurons and central neuropil, were also seen. In freeze-thaw control grafts, neither viable neurons nor central neuropil were observed. Retrograde tracing with Fast Blue and Diamidino Yellow demonstrated that neurons within the FSC graft extended axons into the host spinal cord at least for 2 mm from both the rostral and caudal host-graft interfaces. We conclude that viable FSC grafts within semipermeable guidance channels may serve both as a permissive bridge for longitudinally directed axonal growth and a potential relay for conveying information across a lesion site in the adult rat spinal cord.