失交感神经支配对周围神经再生影响的实验研究

Impact of loss of sympathetic innervation on peripheral nerve regeneration:an experimental study with rats

目的观察失交感神经支配对周围神经损伤后再生的影响。方法切除大鼠一侧颈中交感神经节,切断并吻合双侧正中神经。于手术后1、2、4、8周,分别检测双侧趾浅屈肌复合动作电位(CMAP)、正中神经感觉神经活动电位(SNAP)、吻合口以远的有髓纤维计数和超微结构观察,趾浅屈肌最大肌收缩力及其肌肉湿重等指标,对上述指标进行双侧比较。结果各组动物实验侧的各项指标(19.9μV±2.7μV、11.8mV±1.7mV)均低于对照侧(25.1μV±1.8μV、18.0μV±1.0μV)(均P<0·05)。超微结构观察结果与实验检测指标相符。结论去交感神经支配不利于周围神经损伤后再生,周围神经营养血管的基础紧张被消除导致神经失营养可能是重要原因。交感神经对失神经支配的骨骼肌可能具有营养和保护作用。

Objective To investigate the impact of loss of sympathetic innervation on peripheral nerve regeneration. Methods Thirty-two SD rats underwent resection of the fight middle cervical ganglion and excision and re-anastomosis of bilateral medium nerve, and then were randomly divided into 4 equal groups to undergo the following experiments. One, 2, 3, and 4 weeks later the sensory nerve action potentials （SNAPs） of bilateral medium nerves 5 mm from the anastomotic stoma and the compound muscle action potentials （CMAPs） of bilateral superficial digital flexor muscles were measured with stimulating and recording electrodes. Specimens of the distal part of bilateral medium nerves 5 mm from the anastomotic stoma were collected to calculate the number of medulated fibers by electron microscopy. The tendons of bilateral superior digital flexor muscles were cut ant the wrist, isolated to the terminal points, ligated, and connected to a sensor so as to record the maximum contraction power. The superior digital flexor muscle was completely resected to be weighted. Results CMAP failed to be recorded 1 week later. The wave amplitude of the nerve at the affected side increased along with time, however, the CMAP wave amplitudes of the affected side were all significantly lower than those of the healthy side （ all P 〈 0.05 ）. The SNAP wave amplitudes of the medium nerve of beth sides increased along with the time. The SNAP levels 4 and 8 weeks later of the affected side were beth lower than those of the healthy side （ beth P 〈 0.05 ）. The number of medulated fibers of the medium nerve increased along with the time, however, the number of the affected side were significantly lower than those of the healthy side （ all P 〈 0.05 ）. Electron microscopy showed degeneration of medulla in bilateral medium nerves 1 week later, and newborn medulated fibers began to be seen since 2 weeks later. However, there were a greater number and more complete structure in the healthy side in comparison with the affected side. The wet weights of bilateral superior digital flexor muscles decreased 2 weeks later and then began to increase gradually. However, the wet weight 4 and 8 weeks later were significantly greater in the healthy side then in the affected side （ beth P 〈 0. 05 ）. Conclusion Resection of sympathetic nerve is advantageous on nerve regeneration.