周围神经损伤后脊髓神经元形态及神经活性物质变化的研究

STUDIES ON THE CHANGES OF MORPHOMETRY AND NEUROPEPTIDE OF SPINAL NEURONS AFTER PERIPHERAL NERVE INJURY/

为观测周围神经损伤，尤其是晚期损伤后，脊髓神经元形态、神经活性物质变化及其功能状态，采用切断大鼠坐骨神经，通过辣根过氧化物酶逆行示踪、免疫组化，并结合计算机图像分析等方法，对脊髓前角运动神经元形态及降钙素基因相关肽、胆碱乙酰转移酶和脊髓后角Ｐ物质变化进行定量分析。结果：①前角细胞胞体伤后３周肿胀，６周恢复正常，１２周萎缩２７％。树突持续性收缩，至１２周萎缩５３％。胞体和树突２４周与１２周相似，均无进一步变化。②降钙素基因相关肽神经损伤１周后，即在脊髓前角运动神经元中升至最高并持续４周，８周恢复正常，观察２４周无明显变化；胆碱乙酰转移酶在脊髓前角运动神经元中无明显变化；Ｐ物质在脊髓后角于损伤２～６周下降至最低，１６周恢复正常；而降钙素基因相关肽在脊髓后角则无明显变化。认为，晚期周围神经损伤，从形态学及神经活性物质的变化来看，脊髓神经元的功能活动仍保持在一定水平，具有修复价值。

To observe the change of morphology and neuropeptide in the spinal neurons in order to clarify the functional state after injury of peripheral nerves is especially in the late stage. Sciatic nerves were cut with their proximal segments in the preparation of a model of peripheral nerve injury. Combination of horseradish peroxidase retrograde tracing、 immunohistochemistry and computer image analysis the changes in the morphometry of the perikarya of ventral horn neurons of the spinal cord, the quantitative changes of substance P (SP). Calcitonin gene related peptide (CGRP) in dorsal horn and CGRP and choline acetyransferase (CHAT) in ventral horn of the spinal cord were examed. The results showd: (1) At the 3rd week after injury, swollen perikarya of the ventral horn neurons were observed, subseauently the sweling of perikarya was decreased tile the 6th week the neurons recovered to their normal size. At the 12th week the neurons were generally stable in their size, shortening of the dendrites was seen in 27% of the neurons. (2) The dendrites of the neurons progressively contracted till at the 12th week 53% of them were degenerated. The results of the 24th week were similar to the that at the 12th week. (3) CGRP in the ventral horn of the spinal cord was elevated to the highest point after 1 week of injury, that lasting for 4 weeks and 8 weeks later, the lever of CGRP returned to normal. From 20th to 24th week, there was no obvious changes of CHAT in the ventral horn of the spinal cord during observation. (4) SP went to the lowest point in the dorsal horn during 2～6 weeks, then recovered slowly, and beiny normal again after 16 weeks, however, CGRP was changed slightly. The results indicated that although a series of degenerating changes occurred in the neurons of the spinal cord during the late peripheral nerve injury, but the functional activity of the central meurons still was maintained at a certain level.