An electron microscopic analysis of abnormal ependymal cell proliferation and envelopment of sprouting axons following spinal cord transection in the rat
An electron microscopic analysis of abnormal ependymal cell proliferation and envelopment of sprouting axons following spinal cord transection in the rat
复制标题
大鼠脊髓横断后异常室管膜细胞增殖和发芽轴突包络的电子显微镜分析
作者：
M. A. Matthews;M. S. St Onge;C. L. Faciane
摘要在一系列Long Evans蒙头大鼠的脊髓横断术中，损伤部位附近的神经纤维和白质成分迅速退化，并出现各种反应性细胞成分，它们摄取坏死性碎片，在损伤留下的缺损处产生结缔组织基质。在病变区和邻近脊髓节段内发现的非神经性成分中，有大量的室管膜细胞从正常位置移位。这种异常的增殖产生了广泛的室管膜细胞索和巢，其中一些与中央管内的细胞保持毗邻，而另一些则在灰质中发现了几个100μm远的簇状细胞。具有明显管腔的玫瑰花环通常出现在这样的细胞聚集体中，并且在排列上类似于实验操作后原始神经上皮细胞所显示的模式(Watterson，1965)。电子显微镜下可见典型的椭圆形常染色质核，胞浆苍白，内含浓密的细丝。对花环状管腔的检查显示正常的顶端特化，包括具有基底体的纤毛、微绒毛和大量的透明带粘连的细胞质内空泡形成异常的微绒毛和纤毛，这与某些室管膜瘤的模式相似(Fu等，1974)。在损伤后15-45天期间，轴突萌发到瘢痕基质和邻近的受侵蚀的脊髓节段。与异常室管膜细胞相对的纤维被它们包裹，形成典型的“中轴突”。随着术后时间的延长，直到90DPO，单个细胞内可见3-8个纤维组。
SummaryTransection of the spinal cord in a series of Long Evans hooded rats results in a rapid degeneration of elements of the neuropil and white matter adjacent to the lesion site, and in the appearance of a wide variety of reactive cellular elements which ingest necrotic debris and produce a connective tissue matrix in the defect left by the lesion. Included among the non-neuronal elements found within the lesion zone and adjacent spinal cord segments cranial to the lesion were large clusters of ependymal cells displaced from their normal location. This aberrant proliferation produces extensive cords and nests of ependymal cells some of which maintain contiguity with those elements lining the central canal while other clusters were found several 100 μm distant in the gray matter. Rosettes with distinct lumina often occurred in such cellular aggregates and were similar in arrangement to those patterns displayed by primitive neuroepithelial cells following experimental manipulation (Watterson, 1965). Electron microscopy revealed typical oval euchromatin nuclei with a pale cytoplasm containing concentrations of filaments. Examination of rosette lumina revealed normal apical specializations including cilia with basal bodies, microvilli, and numerous zonulae adherentes Intracytoplasmic vacuole formation with abnormal microvilli and cilia were reminiscent of patterns described in certain ependymomas (Fu et al., 1974).During the period between 15–45 days following injury, axons sprout into the scar matrix and along the adjacent, eroded cord segments. Those fibers which became apposed to the aberrant ependymal cells were enveloped by them and a typical “mesaxon” was formed. With increasing postoperative periods until 90 dpo, groups of 3–8 fibers could be found enclosed within a single cell.