ULTRASTRUCTURAL STUDY OF REMYELINATION IN AN EXPERIMENTAL LESION IN ADULT CAT SPINAL CORD

作者：Mary Bartlett Bunge, Richard P. Bunge, Hans Beat Ris · 发表于：The Journal of Cell Biology · 年份：1961 · DOI：10.1083/jcb.10.1.67 · 被引用次数：391 · 研究领域：Veterinary Orthopedics and Neurology、Neurogenesis and neuroplasticity mechanisms、Glioma Diagnosis and Treatment

This report presents ultrastructural observations on the cytological events that attend myelin formation occurring in the wake of demyelination 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 OsO(4) 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 sam...