A NEW APPROACH TOWARD ANALYZING PERIPHERAL-NERVE FIBER POPULATIONS .2. FORESHORTENING OF REGENERATED INTERNODES CORRESPONDS TO REDUCED SHEATH THICKNESS
A NEW APPROACH TOWARD ANALYZING PERIPHERAL-NERVE FIBER POPULATIONS .2. FORESHORTENING OF REGENERATED INTERNODES CORRESPONDS TO REDUCED SHEATH THICKNESS
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DOI：
10.1097/00005072-198501000-00006
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发表时间：
1985-01-01
影响因子：
3.2
通讯作者：
FRIEDE, RL
中科院分区：
文献类型：
--
作者：
BEUCHE, W;FRIEDE, RL
所使用的新方法是基于轴突口径不是影响髓鞘厚度的唯一因素的概念。有必要考虑节间的整个几何比例，因为鞘厚度对应于轴突口径和节间长度之间的关系。这种类型的分析应用于大鼠坐骨神经再生的节间。在年轻成年大鼠中放置损伤后，研究了4、9、18和36周的生存期。数据显示，与正常神经相比，再生纤维的鞘明显更薄，与以前的观察结果一致。然而，这种鞘厚度的减少在数量上对应于再生神经中的节间缩短的程度。节间长度/纤维直径的商平均减少10对应于鞘的相对厚度（轴突直径/纤维直径的商）减少约0.015。显然，再生的髓鞘并不是真正的发育不良;相反，它们适应于节间长度的减少，并且具有与正常纤维相同的关系。在部分受损的神经中，再生纤维和未受损纤维之间的鞘厚度有明显区别。通过散点图证明这一现象为神经病变的定量评估开辟了新的可能性。
The new approach used is based on the concept that axon caliber is not the only factor affecting the thickness of the myelin sheath. It is necessary to consider the entire geometric proportions of the internode, since sheath thickness corresponds to the relationship between axon caliber and the length of the internode. This type of analysis was applied to the regenerated internodes in rat sciatic nerves. Survival periods of 4, 9, 18 and 36 wk were studied after lesions had been placed in young adult rats. The data shows significantly thinner sheaths for regenerated fibers as compared with normal nerves, consistent with previous observations. This reduction in sheath thickness, however, corresponded quantitatively to the degree of foreshortening of internodes in the regenerated nerves. An average reduction of 10 in the quotient internode length/fiber caliber corresponded to a reduction of about 0.015 in the relative thickness of the sheath (quotient axon diameter/fiber diameter). Apaprently, regenerated myelin sheaths are not truly hypoplastic; rather, they are adapted to the reduced internode length, and have the same relationship found for normal fibers. In partially damaged nerves there was a clear distinction in terms of sheath thickness between regenerated fibers and undamaged fibers. Demonstration of this phenomenon by scatter diagrams opens new possibilities for the quantitative assessment of neuropathies.