Jorgensen D, Dyck P J
J Neuropathol Exp Neurol. 1979 Nov;38(6):571-8. doi: 10.1097/00005072-197911000-00001.
Permanent axotomy, by hind limb amputation in kittens, is found by morphometric evaluation at 9 months after amputation to result in failure of ventral and dorsal root myelinated fibers (MFs) to attain adult calibers. The positions of the median diameter and of diameter peaks were unequivocally displaced to smaller diameters, but more so for dorsal than for ventral roots. When fiber spectra of amputated roots were compared with those of kittens at the time of amputation, the median diameter, the position of peaks of diameter histograms, and the diameters of largest MFs were clearly at larger diameters, an indication that axonal development had continued (especially for motor fibers) for some time after amputation. These studies have shown that whereas in adult cats, permanent axotomy results in axonal atrophy, in kittens axonal development continues, but stops short of reaching adult values. As axonal caliber presumably ultimately relates to perikaryal synthesis of protein, one must infer either that the signal to decrease protein synthesis is slow in arriving at the perikarya or that the decreased axonal flow of materials resulting from such a signal is slow and thus allows continued axonal growth for a period after amputation.
通过对小猫进行后肢截肢造成永久性轴突切断，在截肢后9个月进行形态学评估发现，腹侧和背侧神经根有髓纤维（MFs）未能达到成年时的直径。中位直径和直径峰值的位置明显向较小直径偏移，但背根比腹根更明显。将截肢后神经根的纤维谱与截肢时小猫的纤维谱进行比较时，中位直径、直径直方图峰值位置以及最大有髓纤维的直径明显更大，这表明截肢后轴突发育持续了一段时间（尤其是运动纤维）。这些研究表明，在成年猫中，永久性轴突切断会导致轴突萎缩，而在小猫中，轴突发育会继续，但未能达到成年时的值。由于轴突直径最终可能与胞体蛋白质合成有关，人们必须推断，要么是减少蛋白质合成的信号到达胞体的速度很慢，要么是这种信号导致的轴突物质流动减少速度很慢，从而使得截肢后轴突仍能持续生长一段时间。
