FINE-STRUCTURE OF STUMPS OF TRANSECTED NERVE-FIBERS IN SUB-SERIAL SECTIONS
FINE-STRUCTURE OF STUMPS OF TRANSECTED NERVE-FIBERS IN SUB-SERIAL SECTIONS
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DOI：
10.1016/0022-510x(80)90126-4
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发表时间：
1980-01-01
影响因子：
4.4
通讯作者：
BISCHHAUSEN, R
中科院分区：
文献类型：
--
作者：
FRIEDE, RL;BISCHHAUSEN, R
72 小时前横断的 5 根大鼠坐骨纤维的近端残端，根据分离纤维的亚系列电子显微照片的形态测量进行重建。三根纤维显示出广泛的轴突萌芽； 2 没有豆芽但过度肿胀。轴突肿胀中的轴浆总体积近似于任何给定纤维的所有芽中的轴浆体积。因此，当发芽受阻时，可能会发生轴突肿胀。轴突芽主要起源于它们沿纤维下降或上升的节点，在其基底层内运行。受伤后不久，通常在第一天就开始发芽。微管计数显示，靠近受伤端的每根纤维的微管总数增加了大约 10 倍。雪旺细胞表现出不对称肥大，细胞核远端的细胞质明显多于近端的细胞质。雪旺细胞质的增加与轴浆的增加大致相同。雪旺细胞的肥大与细胞质岛或链具有极其可变的细胞器含量有关。这种雪旺细胞质岛可能与轴突芽相混淆。节点处髓鞘的回缩导致纤维轮廓提示部分脱髓鞘。节点伪足的回缩产生多余的基底层环。迁移细胞可见于纤维外部或基底层下方，优先选择节点区域或纤维残端。它们对轴突或髓磷脂的行为不同：它们像未成熟的雪旺细胞一样包含轴突芽；同时，同一细胞可能像巨噬细胞一样侵入髓鞘。还注意到退化和再生现象的其他奇怪的重叠，包括轴突芽穿过其亲本轴突髓鞘隔离器的内腔。
The proximal stumps of 5 rat sciatic fibers, transected 72 h earlier, were reconstructed on the basis of morphometry in subserial electron micrographs of isolated fibers. Three fibers showed extensive axon sprouting; 2 had no sprouts but were excessively swollen. The total volume of axoplasm in the axon swellings approximated the volume of axoplasm in all sprouts of any given fiber. Axonal swelling therefore may ensue when sprouting is frustrated. Axon sprouts originated mostly at nodes from where they descended or ascended along the fiber, running within its lamina basalis. Sprouting began soon after injury, usually within the first day. Counts of microtubules showed an approximately 10-fold increase in the total number of tubules per fiber toward the injured end. Schwann cells showed asymmetric hypertrophy, having distinctly more cytoplasm distally than proximally to the nucleus. The increase in Schwannian cytoplasm occurred roughly pari-passu with the increases in axoplasm. Hypertrophy of Schwann cells was associated with cytoplasmic islands or strands having an extremely variable content of organelles. Such islands of Schwannian cytoplasm may be confused with axon sprouts. Retraction of the myelin sheaths at nodes results in fiber profiles suggestive of partial demyelination. Retraction of nodal pseudopodia produces redundant loops of lamina basalis. Migratory cells are seen outside the fibers or underneath their lamina basalis having a preference for nodal regions or for the fiber stump. They behave differently toward axon or myelin: they encompass axon sprouts as do immature Schwann cells; simultaneously the same cell may invade myelin sheaths like a macrophage. Other curious overlaps of degenerative and regenerative phenomena were noted, including an axon sprout tunneling through the lumen of the sequester of the myelin sheath of its parent axon.