Immunohistochemical Study of the Effect on Motor Cortex Stimulation for Deafferentation Pain; Comparison of c-Fos Expression Sites

根据已知的疼痛标志物c-fos基因评价运动皮质刺激疗法(MCS)对去传入性疼痛的疗效。[材料]成年猫15只，体质量1.5~3.5 kg。[方法]猫分为三组：三叉神经节损毁后去传入痛组、三叉神经节损毁后应用MCS组和对照组。免疫组织化学方法检测c-fos的表达部位和水平。[结果]去传入痛组和MCS组大鼠三叉神经脊束核c-Fos阳性细胞百分比均增加，但MCS组左侧增加较小。去传入痛组双侧扣带回c-Fos阳性细胞百分比增加，但MCS组增加更明显。尽管去传入痛组和MCS组双侧岛叶和顶盖c-Fos阳性细胞的百分比增加，但在统计学上没有显著差异。双侧去传入痛组脑桥灰质和中脑导水管周围灰质c-Fos阳性细胞百分比增加。MCS组与对照组比较差异无统计学意义。[结论]扣带回、岛叶和顶盖在去传入后被激活。这种激活与去传入性疼痛的发生有关。MCS的止痛作用不依赖于脑干下行止痛机制。扣带回的激活似乎是MCS镇痛机制中的一个因素。

The effect of motor cortex stimulation therapy (MCS) for deafferentation pain evaluated on the basis of c-fos gene, a known pain marker. [Materials] Fifteen mature cats, weighing 1.5-3.5 kilograms were used. [Methods] The cats were divided into three groups: a deafferentation pain group in which the trigeminal ganglion was destroyed, an MCS group in which MCS was used after destruction of the trigeminal ganglion, and a control group. Sites and levels of c-fos expression were examined immunohistochemically. [Result] The percentage of c-Fos-positive cells in the spinal nucleus of the trigeminus increased in both the deafferentation pain and MCS groups, however, the increase was smaller in the left side of the brain in the MCS group. In the cingulate gyrus, the percentage of c-Fos-positive cells increased bilaterally in the deafferentation pain group, but the increase was greater in the MCS group. Although the percentage of c-Fos-positive cells in the insula and the parietal operculum increased bilaterally in the deafferentation pain and MCS groups, there were no statistically significant differences between these groups. In the pontine gray and periaqueductal gray matter, the percentage of c-Fos-positive cells in the deafferentation pain group increased bilaterally. There was no significant difference between the MCS group and the control group. [Conclusion] The cingulate gyrus, insula, and pariental operculum are activated after deafferentation. This activation is related to the development of deafferentation pain. Pain relief due to MCS is not dependent on the descending analgesic mechanism of the brain stem. Activation of the cingulate gyrus appears to be a factor in the analgesic mechanism of MCS.