膈神经移位术后神经元再生的实验研究

An experimental study on neuronal regeneration after phrenic nerve transfer

目的通过观察膈神经移位术后大鼠神经元再生情况及其形态学改变,了解该神经移位术后运动和感觉神经元的再生能力。方法采用SD成年雌鼠(10～12周龄,n=11只),一组大鼠膈神经切断后用荧光示踪剂快蓝溶液标记,一周后经心脏灌注4%副甲醛溶液,取出C_(2-5)脊髓节段及背根神经节,切片在荧光显微镜放大250倍下计数快蓝标记的运动神经元和感觉神经元,并测量荧光标记的神经元截面积。另一组大鼠行膈神经移位至肌皮神经,经过6个月的神经再生后,在吻合口远端切断肌皮神经,采用同样方法逆向标记已经完成再生的神经元,一周后如上法取材,计数神经元及测量胞体截面积。结果1.正常大鼠膈神经核含运动神经元[(344.3±10.0)个,(?)±s,下同],截面积为(588.5±31.9)μm^2;含感觉神经元(427.0±54.6)个,截面积为(881.9±86.9)μm^2。2.膈神经移位术后,约有95%的运动神经元(326.0±16.3)个完成了再生,再生的运动神经元胞体表现出轻度肿胀(673.6±25.8)μm^2;只有约60%的感觉神经元完成了再生(255.8±45.2)个,再生的感觉神经元表现出胞体萎缩(668.8±51.1)μm^2。结论膈神经移位后具有良好的神经元再生能力,尤其表现在运动神经元,为术后运动功能恢复创造了重要的先决条件。

Objective The morphologie changes of neurons after phrenie nerve transfer were observed to investigate the regeneration of motor and sensory neurons in rats. Methods Adult female SD rats were used in the study （10- 12 weeks, n= 11）. In one group, the phrenie nerve was cut and labeled by fluorescent tracer fast blue. One week later the rats were sacrificed and peffused with 4% formalin. Spinal cord and dorsal root ganglia （DRG） from C2 to C5 were harvested. Positively labeled motor neurons in the anterior horn of the spinal cord and sensory neurons in DRG were counted and their cell size measured. In the other group, phrenie nerve to musculocutaneous nerve transfer was done. Six months after the surgery, the museuloeutaneous nerve was transected distal to the neurotization site and labeled with fast blue. Tissue harvesting and counting and measuring of the motor and sensory neurons were counted by same method. Results Six months following phrenie nerve transfer, 326.0±16.31 phrenie motoneuruns regenerated into the museuloeutaneous nerve, which was not significantly different from the normal number of phrenie motoneurons （ 344.3± 10.0）. The regenerated motoneurons exhibited a 14% hypertrophy, the soma size being 673.6±25.8μm^2 versus the （588.5 ± 31.9）μm^2 that of normal motoneurons. （ 255.8 ±45.26） of the DRG neurons regenerated, which was significantly lower than the number of normal phrenie DRG neurons（427.0 ± 54.6）. The regenerated phrenie DRG neurons showed a 24% hypotrophy, the soma size being （881.9 ± 86.9） μm^2 versus the （668.8 ±51.1 ） μm^2 that of normal DRG neurons. Conclusion Phrenie nerve has very good regenerative ability in terms of its motoneurons and a relatively insufficient sensory neuronal regeneration.