大鼠三叉神经痛觉传入纤维在感觉根分布特点的研究

Study on specific distribution of afferent fibers in trigeminal sensory root of the rat

目的研究大鼠三叉神经痛觉传入纤维在三叉神经感觉根的分布特点，为实施高度选择性手术治疗三叉神经痛提供实验参考。方法将荧光示踪剂2％荧光金分别注入大鼠三叉神经脊束核各亚核及脑桥核。大鼠存活7d后，取三叉神经感觉根作连续冰冻切片，荧光显微镜下观察三又神经感觉根荧光金在断面的分布情况并进行分析。结果注射到脊束核嘴侧亚核的荧光金经逆行运输后，阳性纤维集中分布于感觉根的外侧，范围局限，纤维直径细小而密集；极间亚核及尾侧亚核注射组的阳性纤维在感觉根的分布相似，亦集中于感觉根外侧，纤维亦较密集，但分布范围较嘴侧亚核注射组稍大。经脑桥核逆行运输的荧光金，显示的阳性纤维主要分布于感觉根的腹侧和内侧，少量分布于中部，纤维间明显分散，没有明确的范围和边界。结论大鼠三叉神经痛觉传入纤维集中分布在感觉根的特定区域，在该部位选择性损伤痛觉传入纤维是可行的。

Objective To study the distribution character of the trigeminal sensory afferent fibers in rat＇ s trigeminal sensory root （RxV） and to explore the possibility of selectively injury of the pain afferent fibers. Methods The retrograde tracer fluorogold （FG） was injected into trigeminal spinal subnucleus and pontine nucleus respectively. After 7 days survival, the rats were sacrificed and the RxV was removed and sectioned. The distribution of FG at RxV was studied under fluorescent microscope and its character was analyzed. Results After being introduced into trigeminal spinal rostral nucleus, the FG could be observed at the lateral portion on the sections of RxV. The fibers were small and concentrated. The interpolaris subnucleus and caudal subnueleus injection group also showed small and concentrated fibers in the lateral portion of RxV, but the distribution area was larger than that of the rostral subnucleus group. While being injected into trigeminal pontine nucleus, the FG positive axons could be found in the ventral, medial and central portion of the RxV cross sections. These fibers were thicker and more scattered compared to those projecting into trigeminal spinal nucleus. Conclusion The fibers relating to transporting pain sensory concentrate at a certain area of rat＇ s RxV, which indicate that selectively injury of the pain afferent fibers of RxV should be possible.