Murakami M, Ide C, Kanaya H
Department of Anatomy, Iwate Medical University School of Medicine, Morioka, Japan.
J Neurosurg. 1989 Aug;71(2):254-65. doi: 10.3171/jns.1989.71.2.0254.
In order to examine nerve regeneration under conditions in which the basal laminae of the glial limiting membranes (GLM) and blood vessels were preserved intact, the intraorbital segment of adult rat optic nerve was frozen locally. During the next 3 months, degenerative and regenerative changes in axons and glial cells were observed by light and electron microscopy. On the day after treatment, all the myelinated and unmyelinated axons in the central zone of the lesion were damaged. The astrocyte endfeet of the GLM as well as the blood vessels were extensively disrupted, while their basal laminae were preserved apparently intact as a continuous sheet. Three days after treatment, regenerating axons appeared in the central zone of the lesion. They contained various numbers of clear and dense-cored vesicles as well as some smooth endoplasmic reticulum. The regenerating axons gradually increased in number, especially beneath the pial and perivascular surfaces of the lesion, where an abundance of regenerating axons was found 3 months after treatment. A few of these axons were abnormally remyelinated by oligodendrocytes. In addition to this axonal regeneration through the intraoptic nerve compartment, fine regenerating axons were seen growing out through GLM into the pial connective tissue 3 weeks after treatment. Astrocyte endfeet of the GLM became irregular in contour, protruding in a fern-leaf fashion into the pial connective tissue. Fine naked axons grew out through these protrusions and subsequently increased in number, vigorously growing in large bundles both proximally and distally along blood vessels in the pial connective tissue. Bundles of regenerating axons extended as much as 1.5 mm from the site of the lesion 3 months after surgery. These bundles were covered by thin processes of pial or arachnoidal non-neuronal cells, and the regenerating axons remained unmyelinated. The above findings indicate that under well-nourished conditions, adult mammalian optic nerve exhibits considerable regenerative ability.
为了在神经胶质界膜（GLM）和血管的基膜保持完整的条件下检查神经再生情况，对成年大鼠眶内段视神经进行局部冷冻。在接下来的3个月里，通过光镜和电镜观察轴突和神经胶质细胞的退行性和再生性变化。治疗后第一天，损伤中央区所有有髓和无髓轴突均受损。GLM的星形胶质细胞终足以及血管被广泛破坏，而它们的基膜显然作为连续的薄片保持完整。治疗后三天，再生轴突出现在损伤中央区。它们含有数量不等的清亮和有致密核心的小泡以及一些滑面内质网。再生轴突数量逐渐增加，尤其是在损伤的软膜和血管周围表面下方，治疗3个月后在那里发现大量再生轴突。其中一些轴突被少突胶质细胞异常重新髓鞘化。除了通过视神经内部区域的轴突再生外，治疗3周后可见细的再生轴突通过GLM生长到软膜结缔组织中。GLM的星形胶质细胞终足轮廓变得不规则，呈蕨叶状突出到软膜结缔组织中。细的无髓轴突通过这些突起生长出来，随后数量增加，在软膜结缔组织中沿着血管向近端和远端大量生长。术后3个月，再生轴突束从损伤部位延伸多达1.5毫米。这些束被软膜或蛛网膜非神经元细胞的细突起覆盖，再生轴突仍无髓鞘。上述发现表明，在营养良好的条件下，成年哺乳动物视神经表现出相当强的再生能力。
