ULTRASTRUCTURAL STUDY OF REMYELINATION IN AN EXPERIMENTAL LESION IN ADULT CAT SPINAL CORD
ULTRASTRUCTURAL STUDY OF REMYELINATION IN AN EXPERIMENTAL LESION IN ADULT CAT SPINAL CORD
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DOI：
10.1083/jcb.10.1.67
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发表时间：
1961-01-01
期刊：
影响因子：
--
通讯作者：
BUNGE, RP
中科院分区：
文献类型：
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作者：
BUNGE, MB;RIS, H;BUNGE, RP
本文报道了成年猫脊髓脱髓鞘过程中伴随髓鞘形成的细胞学事件的超微结构观察。用脑脊液（c.s.f.）exchange（1，2）.组织从11只猫在9个时间间隔从19到460天，固定在原位取代c.s.f.与缓冲OsO4和Araldite包埋。脱髓鞘后，轴突被片状胶质突起包围。在19天时首次看到偶尔的髓鞘;到64天，所有轴突至少有稀疏的髓鞘。与正常脊髓中的少突胶质细胞或纤维性星形胶质细胞不同，髓鞘形成细胞的细胞质致密，细胞器和细纤维排列紧密。许多髓鞘形成细胞成为瘢痕性星形胶质细胞，并且在460天时，病变充满了它们的纤维填充的过程。髓鞘再生后，少突胶质细胞出现在病变中。吞噬细胞逐渐消失。髓鞘是由片状神经胶质突起围绕轴突螺旋缠绕而形成的。在螺旋的第一圈完成的地方，形成了一个中间轴突。随着细胞质从该过程中丢失，质膜沿着其外表面和细胞质表面沿着聚集在一起，形成致密的髓鞘。只有少量的细胞质被保留;它被限制在轴旁区域，在鞘的外部，一个纵向的脊出现在个人资料作为一个小环。外环的旋转方向与内轴突的旋转方向相同。这些螺旋膜包裹的痕迹也在正常的成年猫和新生猫的脐带中发现。节点存在于髓鞘再生的所有阶段和正常的成年猫和小猫脊髓中。这些观察结果表明，髓鞘在病变中以与正常发育期间首次形成相同的方式重新形成。髓鞘形成的机制基本上类似于周围神经和两栖动物和哺乳动物视神经的髓鞘形成机制，这与目前关于哺乳动物脑和脊髓髓鞘形成机制的观点不一致。这是第一次证明在成年哺乳动物中枢神经组织髓鞘再生。
This report presents ultrastructural observations on the cytological events that attend myelin formation occurring in the wake of de-myelination in adult cat spinal cord. Lesions were induced in subpial cord by cerebrospinal fluid (c.s.f.) exchange (1, 2). Tissue from eleven cats at nine intervals from 19 to 460 days was fixed in situ by replacing c.s.f. with buffered OsO4 and embedded in Araldite. After demyelination, axons are embraced by sheet-like glial processes. An occasional myelin sheath is first seen at 19 days; by 64 days, all axons are at least thinly myelinated. The cytoplasm of the myelin-forming cells, unlike that of either oligodendrocyte or fibrous astrocyte in normal cord, is dense with closely packed organelles and fine fibrils. Many of the myelinogenic cells become scarring astrocytes and at 460 days the lesion teems with their fibril-filled processes. Oligodendrocytes appear in the lesion after remyelination is under way. Phagocytes disappear gradually. A myelin sheath is formed by spiral wrapping of a sheet-like glial process around an axon. Where the first turn of the spiral is completed, a mesaxon is formed. As cytoplasm is lost from the process, the plasma membrane comes together along its outer and cytoplasmic surfaces to form compact myelin. Only a small amount of cytoplasm is retained; it is confined to the paramesaxonal region and, on the sheath exterior, to a longitudinal ridge which appears in profile as a small loop. This outer loop has the same rotational orientation as the inner mesaxon. These vestiges of spiral membrane wrapping are also found in normal adult and new-born cat cord. Nodes are present in all stages of remyelination and in normal adult cat and kitten cord. These observations suggest that myelin is reformed in the lesion in the same way it is first formed during normal development. The mechanism of myelin formation is basically similar to that proposed for peripheral nerve and amphibian and mammalian optic nerve; it does not agree with present views on the mechanism of myelinogenesis in mammalian brain and cord. This is the first demonstration of remyelination in adult mammalian central nervous tissue.