Han Dong, Lu Jiuzhou, Xu Lei, Xu Jianguang
Key Laboratory of Hand Reconstruction, Ministry of Health Shanghai 200032, China ; Shanghai Key Laboratory of Peripheral Nerve and Microsurgery Shanghai 200032, China ; Department of Hand Surgery, Huashan Hospital, Fudan University Shanghai 200040, China.
Int J Clin Exp Med. 2015 Feb 15;8(2):2392-8. eCollection 2015.
There are 2 critical steps in neural regeneration: nerve fibres successfully crossing the suture and restoration of neuromuscular transmission. For the second step, the compound muscle action potential (CMAP) is the standard electrophysiological technique used to assess regeneration, but it is difficult to detect changes in the CMAP during early regeneration after nerve repair. There is a need for better, noninvasive quantitative electrophysiological techniques to assess regeneration in an earlier stage after nerve repair. In this study, we utilized 2 measures, CMAP and single-fibre electromyography (SFEMG), in a rat model of nerve repair. The model was generated by separating the sciatic nerve of the rat hindlimb from the tibial nerve in Sprague-Dawley rats. CMAP and SFEMG were measured in each rat at 1, 2, 3, 4, and 6 weeks after the operation. The muscle weight was measured and both the general structure of the muscle and the changes in muscle atrophy were examined using haematoxylin and eosin staining protocols. The nerve electrophysiological data could be detected at 2 weeks after surgery initially and more data could be collected with passing time. During the period ranging from 2 to 4 weeks after surgery, parameters of SFEMG recordings changed significantly while the CMAP amplitude did not increase until 6 weeks after surgery. While the fibre density (FD) at 2 weeks after surgery was 0.27 ± 0.31, there was a significant increase at 3 weeks relative to 2 weeks (P < 0.01), and the FD increased further at 4 weeks (P < 0.01). The action potential mean consecutive difference (MCD) was significantly higher (60.50 ± 3.53 μs) in the second week relative to the third week (41.12 ± 5.08 μs) after the operation. The results indicated that SFEMG was more sensitive than CMAP amplitudes in detecting neuromuscular transmission after nerve repair. The findings of nerve electrophysiological experiments were consistent with the observed degree of muscle recovery. The SFEMG can be used to detect the very early reinnervation of the muscle more sensitively than CMAP. The ratio of affected muscle weight to unaffected muscle weight was decreased at 2 weeks after surgery (59.01%), continued to decrease significantly at 3 weeks (51.24%), and was restored at 6 weeks. A combination of SFEMG and CMAP can show the dynamic progression of the muscle reinnervation process.
神经纤维成功穿过缝合处以及神经肌肉传递的恢复。对于第二步，复合肌肉动作电位（CMAP）是用于评估再生的标准电生理技术，但在神经修复后的早期再生过程中很难检测到CMAP的变化。因此需要更好的、非侵入性的定量电生理技术来在神经修复后的更早阶段评估再生情况。在本研究中，我们在大鼠神经修复模型中使用了两种测量方法，即CMAP和单纤维肌电图（SFEMG）。该模型是通过在Sprague-Dawley大鼠中分离大鼠后肢的坐骨神经和胫神经建立的。在术后1、2、3、4和6周对每只大鼠测量CMAP和SFEMG。测量肌肉重量，并使用苏木精和伊红染色方案检查肌肉的总体结构以及肌肉萎缩的变化。术后2周最初可检测到神经电生理数据，随着时间推移可收集到更多数据。在术后2至4周期间，SFEMG记录参数发生显著变化，而CMAP幅度直到术后6周才增加。术后2周时纤维密度（FD）为0.27±0.31，相对于2周，3周时显著增加（P<0.01），4周时FD进一步增加（P<0.01）。术后第二周动作电位平均连续差值（MCD）（60.50±3.53μs）显著高于第三周（41.12±5.08μs）。结果表明，在检测神经修复后的神经肌肉传递方面，SFEMG比CMAP幅度更敏感。神经电生理实验结果与观察到的肌肉恢复程度一致。与CMAP相比，SFEMG能够更敏感地检测到肌肉的极早期再支配。术后2周时患侧肌肉重量与未患侧肌肉重量之比降低（59.01%），3周时继续显著降低（51.24%），6周时恢复。SFEMG和CMAP相结合可以显示肌肉再支配过程的动态进展。
